diff --git a/.flowconfig b/.flowconfig
index 404d39b..4010e54 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -1,7 +1,7 @@
 [options]
 unsafe.enable_getters_and_setters=true
 suppress_comment=.*\\$FlowIssue
-module.system.node.resolve_dirname=src
+module.system.node.resolve_dirname=es6
 module.system.node.resolve_dirname=node_modules
 
 [ignore]
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0d2d4c7..6aec1de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Change Log
 
+0.2.0
+### Added
+- `concat` to concatenate multiple `DataFrame`s or `Series`
+- `append` for `DataFrame`
+- `transpose` for DataFrame`
+
 0.1.28
 ### Added
 - `rename` for `DataFrame` and `Series`
diff --git a/dist/__tests__/core/frame.js b/dist/__tests__/core/frame.js
index d618f62..0ad975f 100644
--- a/dist/__tests__/core/frame.js
+++ b/dist/__tests__/core/frame.js
@@ -978,13 +978,6 @@ describe('frame', function () {
     });
   });
 
-  describe('pivot_table', function () {
-    it('pivots', function () {
-      var df = new _frame2.default([{ a: 1, b: 1, c: 1, d: 3 }, { a: 1, b: 1, c: 2, d: 8 }, { a: 1, b: 2, c: 1, d: 9 }, { a: 1, b: 2, c: 2, d: 10 }, { a: 2, b: 1, c: 1, d: 1 }, { a: 2, b: 1, c: 2, d: 4 }, { a: 2, b: 2, c: 1, d: 1 }, { a: 2, b: 2, c: 2, d: 3 }, { a: 2, b: 2, c: 2, d: 3 }]);
-
-      console.log(df.pivot_table(['a', 'b'], 'c', 'd'));
-    });
-  });
 
   describe('rename', function () {
     it('renames one Series in the DataFrame', function () {
@@ -1013,4 +1006,52 @@ describe('frame', function () {
       expect(df.length).toEqual(5);
     });
   });
+
+  describe('append', function () {
+    it('Appends a DataFrame to another when ignore_index is false', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([{ x: 2, y: 2 }, { x: 3, y: 3 }, { x: 4, y: 4 }], { index: [2, 3, 4] });
+
+      var df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a DataFrame to another when ignore_index is true', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([{ x: 2, y: 2 }, { x: 3, y: 3 }, { x: 4, y: 4 }], { index: [2, 3, 4] });
+
+      var df3 = df1.append(df2, true);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Appends an empty DataFrame to another', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([]);
+
+      var df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
+
+  describe('transpose', function () {
+    it('Tranposes a DataFrame by flipping indexes and columns', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = df1.transpose();
+
+      expect(df2.columns.toArray()).toEqual([1, 2, 3]);
+      expect(df2.index.toArray()).toEqual(['x', 'y']);
+      expect(df2.get(1).index.toArray()).toEqual(['x', 'y']);
+
+      var df3 = df2.transpose();
+      expect(df3.columns.toArray()).toEqual(['x', 'y']);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('x').index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
 });
\ No newline at end of file
diff --git a/dist/__tests__/core/reshape/concat.js b/dist/__tests__/core/reshape/concat.js
new file mode 100644
index 0000000..411b7ac
--- /dev/null
+++ b/dist/__tests__/core/reshape/concat.js
@@ -0,0 +1,86 @@
+'use strict';
+
+var _immutable = require('immutable');
+
+var _immutable2 = _interopRequireDefault(_immutable);
+
+var _frame = require('../../../core/frame');
+
+var _frame2 = _interopRequireDefault(_frame);
+
+var _series = require('../../../core/series');
+
+var _series2 = _interopRequireDefault(_series);
+
+var _concat = require('../../../core/reshape/concat');
+
+var _concat2 = _interopRequireDefault(_concat);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+describe('concat', function () {
+  describe('concat Series', function () {
+    it('Concatenates two Series without ignoring index', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      var series3 = (0, _concat2.default)([series1, series2]);
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 0, 1, 2, 3]);
+    });
+
+    it('Concatenates two Series with ignore index', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      var series3 = (0, _concat2.default)([series1, series2], { ignore_index: true });
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5, 6, 7]);
+    });
+
+    it('Throws an error if the first object in concat is a Series ' + 'and any of the rest are not', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      expect(function () {
+        return (0, _concat2.default)([series1, series2, []], { ignore_index: true });
+      }).toThrow();
+      expect(function () {
+        return (0, _concat2.default)(_immutable2.default.List([series1, series2, []]), { ignore_index: true });
+      }).toThrow();
+    });
+  });
+
+  describe('concat DataFrame', function () {
+    it('Concatenates two DataFrames without ignoring index', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2]);
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 0, 1, 2]);
+    });
+
+    it('Concatenates two DataFrames with index ignored', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2], { ignore_index: true });
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Concatenates two DataFrames along axis = 1 without ignoring index', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2], { axis: 1 });
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(frame3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').name).toEqual('x.x');
+      expect(frame3.get('y.x').values.toArray()).toEqual([3, 4, 5]);
+      expect(frame3.get('y.x').name).toEqual('y.x');
+    });
+  });
+});
\ No newline at end of file
diff --git a/dist/__tests__/core/series.js b/dist/__tests__/core/series.js
index 2695249..2a0cdd9 100644
--- a/dist/__tests__/core/series.js
+++ b/dist/__tests__/core/series.js
@@ -658,4 +658,22 @@ describe('series', function () {
       });
     });
   });
+
+  describe('append', function () {
+    it('Appends a Series to another when ignore_index is false', function () {
+      var ds1 = new _series2.default([1, 2, 3], { index: [1, 2, 3] });
+      var ds2 = new _series2.default([2, 3, 4], { index: [2, 3, 4] });
+      var ds3 = ds1.append(ds2);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a Series to another when ignore_index is true', function () {
+      var ds1 = new _series2.default([1, 2, 3], { index: [1, 2, 3] });
+      var ds2 = new _series2.default([2, 3, 4], { index: [2, 3, 4] });
+      var ds3 = ds1.append(ds2, true);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+  });
 });
\ No newline at end of file
diff --git a/dist/core/frame.js b/dist/core/frame.js
index 789b88e..2766912 100644
--- a/dist/core/frame.js
+++ b/dist/core/frame.js
@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.mergeDataFrame = undefined;
+exports._concatDataFrame = exports.mergeDataFrame = undefined;
 
 var _toConsumableArray2 = require('babel-runtime/helpers/toConsumableArray');
 
@@ -55,6 +55,10 @@ var _series2 = _interopRequireDefault(_series);
 
 var _utils = require('./utils');
 
+var _concat = require('./reshape/concat');
+
+var _concat2 = _interopRequireDefault(_concat);
+
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
 var parseArrayToSeriesMap = function parseArrayToSeriesMap(array, index) {
@@ -105,6 +109,7 @@ var DataFrame = function (_NDFrame) {
         if (data instanceof _immutable2.default.Map && !(data.get(k) instanceof _series2.default)) throw new Error('Map must have [column, series] key-value pairs');
 
         if (data instanceof _immutable2.default.Map) return [k, data.get(k).copy()];
+
         throw new Error('Data is not Map');
       }));
       _this.set_axis(1, _this._data.keySeq());
@@ -553,19 +558,13 @@ var DataFrame = function (_NDFrame) {
           return _this12.get(k).variance();
         }), { index: this.columns.toArray() });
       } else if (axis === 1) {
-        var _ret = function () {
-          var means = _this12.mean(axis).values;
-          return {
-            v: new _series2.default(_immutable2.default.Range(0, _this12.length).map(function (idx) {
-              return _this12.values.get(idx).reduce(function (s, k) {
-                var diff = k - means.get(idx);
-                return s + diff * diff / (_this12.columns.size - 1);
-              }, 0);
-            }).toArray(), { index: _this12.index })
-          };
-        }();
-
-        if ((typeof _ret === 'undefined' ? 'undefined' : (0, _typeof3.default)(_ret)) === "object") return _ret.v;
+        var means = this.mean(axis).values;
+        return new _series2.default(_immutable2.default.Range(0, this.length).map(function (idx) {
+          return _this12.values.get(idx).reduce(function (s, k) {
+            var diff = k - means.get(idx);
+            return s + diff * diff / (_this12.columns.size - 1);
+          }, 0);
+        }).toArray(), { index: this.index });
       }
 
       throw new _exceptions.InvalidAxisError();
@@ -715,92 +714,28 @@ var DataFrame = function (_NDFrame) {
   }, {
     key: 'pivot_table',
     value: function pivot_table(index, columns, values) {
-      var _this16 = this;
-
       var aggfunc = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : 'sum';
 
       throw new Error('Not implemented');
-      var validateCols = function validateCols(cols) {
-        if (Array.isArray(cols)) {
-          cols.forEach(function (c) {
-            return _this16._assertColumnExists(c);
-          });
-          return _immutable2.default.List(cols);
-        } else if (cols instanceof _immutable2.default.List) {
-          cols.forEach(function (c) {
-            return _this16._assertColumnExists(c);
-          });
-          return cols;
-        } else if (typeof cols === 'string') {
-          _this16._assertColumnExists(cols);
-          return _immutable2.default.List.of(cols);
-        }
-
-        throw new TypeError('cols must be Array, Immutable.List, or string');
-      };
-
-      var indexCols = validateCols(index);
-      var columnCols = validateCols(columns);
-      var valuesCols = validateCols(values);
-
-      var pivotMap = _immutable2.default.Map({});
-
-      this.index.map(function (indexVal, idx) {
-        var key = indexCols.map(function (c) {
-          return _this16.get(c).iloc(idx);
-        }).concat(columnCols.map(function (c) {
-          return _this16.get(c).iloc(idx);
-        }));
-        var val = _this16.get(valuesCols.get(0)).iloc(idx);
-        if (pivotMap.has(key)) {
-          switch (aggfunc) {
-            case 'sum':
-              val += pivotMap.get(key);
-              break;
-            default:
-              throw new Error('not implemented for aggs');
-          }
-        }
-
-        pivotMap = pivotMap.set(key, val);
-      });
-
-      var indexMap = _immutable2.default.OrderedMap({});
-      var columnsMap = _immutable2.default.OrderedMap({});
-
-      pivotMap.entrySeq().forEach(function (_ref9) {
-        var _ref10 = (0, _slicedToArray3.default)(_ref9, 2),
-            k = _ref10[0],
-            v = _ref10[1];
-
-        var indexKey = k.slice(0, indexCols.size - 1);
-        console.log(k);
-        console.log(indexKey);
-        if (indexMap.hasIn(indexKey)) indexMap = indexMap.setIn(indexKey, indexMap.getIn(indexKey).concat([k[indexCols.size - 1]]));else indexMap = indexMap.setIn(indexKey, _immutable2.default.List.of(k[indexCols.size - 1]));
-        columnsMap = columnsMap.setIn(k.slice(indexCols.size, k.length));
-      });
-
-      console.log(indexMap);
-      console.log(columnsMap);
-      return pivotMap;
     }
   }, {
     key: '_cumulativeHelper',
     value: function _cumulativeHelper() {
-      var _this17 = this;
+      var _this16 = this;
 
       var operation = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : _utils.OP_CUMSUM;
       var axis = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 0;
 
       if (axis === 0) {
         return new DataFrame(_immutable2.default.Map(this.columns.map(function (c) {
-          return [c, _this17.get(c)._cumulativeHelper(operation)];
+          return [c, _this16.get(c)._cumulativeHelper(operation)];
         })), this.kwargs);
       } else if (axis === 1) {
         return new DataFrame(this.values.map(function (row) {
           return (0, _utils.generateCumulativeFunc)(operation)(row);
         }), this.kwargs);
-      } else throw new Error('invalid axis');
+      }
+      throw new Error('invalid axis');
     }
   }, {
     key: 'cumsum',
@@ -832,17 +767,33 @@ var DataFrame = function (_NDFrame) {
     }
   }, {
     key: 'rename',
-    value: function rename(_ref11) {
-      var _this18 = this;
+    value: function rename(_ref9) {
+      var _this17 = this;
 
-      var columns = _ref11.columns;
+      var columns = _ref9.columns;
 
       return new DataFrame(_immutable2.default.OrderedMap(this.columns.map(function (prevCol) {
         var nextCol = columns.get(prevCol);
-        if (typeof nextCol === 'undefined') return [prevCol, _this18._data.get(prevCol)];
-        return [nextCol, _this18._data.get(prevCol).rename(nextCol)];
+        if (typeof nextCol === 'undefined') return [prevCol, _this17._data.get(prevCol)];
+        return [nextCol, _this17._data.get(prevCol).rename(nextCol)];
       })), { index: this.index });
     }
+  }, {
+    key: 'append',
+    value: function append(other) {
+      var ignore_index = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
+      return _concatDataFrame([this, other], { ignore_index: ignore_index });
+    }
+  }, {
+    key: 'transpose',
+    value: function transpose() {
+      var _this18 = this;
+
+      return new DataFrame(_immutable2.default.OrderedMap(this.index.map(function (index, idx) {
+        return [index, new _series2.default(_this18.values.get(idx), { index: _this18.columns.toList() })];
+      })));
+    }
   }, {
     key: 'kwargs',
     get: function get() {
@@ -901,10 +852,10 @@ var DataFrame = function (_NDFrame) {
 
       this.set_axis(0, (0, _utils.parseIndex)(index, this._data.get(this.columns.get(0)).values));
 
-      this._data.mapEntries(function (_ref12) {
-        var _ref13 = (0, _slicedToArray3.default)(_ref12, 2),
-            k = _ref13[0],
-            v = _ref13[1];
+      this._data.mapEntries(function (_ref10) {
+        var _ref11 = (0, _slicedToArray3.default)(_ref10, 2),
+            k = _ref11[0],
+            v = _ref11[1];
 
         v.index = _this21.index;
       });
@@ -962,8 +913,7 @@ var innerMerge = function innerMerge(df1, df2, on) {
               row2 = _step2$value[0],
               _2 = _step2$value[1];
 
-          var match = true;
-          var _iteratorNormalCompletion3 = true;
+          var match = true;var _iteratorNormalCompletion3 = true;
           var _didIteratorError3 = false;
           var _iteratorError3 = undefined;
 
@@ -992,23 +942,21 @@ var innerMerge = function innerMerge(df1, df2, on) {
           }
 
           if (match) {
-            (function () {
-              var rowData = {};
+            var rowData = {};
 
-              on.forEach(function (k) {
-                rowData[k] = row1.get(k);
-              });
+            on.forEach(function (k) {
+              rowData[k] = row1.get(k);
+            });
 
-              cols1.forEach(function (k, idx) {
-                rowData[cols1Rename.get(idx)] = row1.get(k);
-              });
+            cols1.forEach(function (k, idx) {
+              rowData[cols1Rename.get(idx)] = row1.get(k);
+            });
 
-              cols2.forEach(function (k, idx) {
-                rowData[cols2Rename.get(idx)] = row2.get(k);
-              });
+            cols2.forEach(function (k, idx) {
+              rowData[cols2Rename.get(idx)] = row2.get(k);
+            });
 
-              data.push(rowData);
-            })();
+            data.push(rowData);
           }
         };
 
@@ -1084,8 +1032,7 @@ var outerMerge = function outerMerge(df1, df2, on) {
               row2 = _step5$value[0],
               idx_2 = _step5$value[1];
 
-          var match = true;
-          var _iteratorNormalCompletion6 = true;
+          var match = true;var _iteratorNormalCompletion6 = true;
           var _didIteratorError6 = false;
           var _iteratorError6 = undefined;
 
@@ -1174,45 +1121,41 @@ var outerMerge = function outerMerge(df1, df2, on) {
 
   matched1.forEach(function (m, idx) {
     if (!m) {
-      (function () {
-        var rowData = {};
-        on.forEach(function (k) {
-          rowData[k] = df1.get(k).iloc(idx);
-        });
+      var rowData = {};
+      on.forEach(function (k) {
+        rowData[k] = df1.get(k).iloc(idx);
+      });
 
-        cols1.forEach(function (k) {
-          var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_x' : k;
-          rowData[nextColName] = df1.get(k).iloc(idx);
-        });
+      cols1.forEach(function (k) {
+        var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_x' : k;
+        rowData[nextColName] = df1.get(k).iloc(idx);
+      });
 
-        cols2.forEach(function (k) {
-          var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_y' : k;
-          rowData[nextColName] = null;
-        });
-        data.push(rowData);
-      })();
+      cols2.forEach(function (k) {
+        var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_y' : k;
+        rowData[nextColName] = null;
+      });
+      data.push(rowData);
     }
   });
 
   matched2.forEach(function (m, idx) {
     if (!m) {
-      (function () {
-        var rowData = {};
-        on.forEach(function (k) {
-          rowData[k] = df2.get(k).iloc(idx);
-        });
+      var rowData = {};
+      on.forEach(function (k) {
+        rowData[k] = df2.get(k).iloc(idx);
+      });
 
-        cols1.forEach(function (k) {
-          var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_x' : k;
-          rowData[nextColName] = null;
-        });
+      cols1.forEach(function (k) {
+        var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_x' : k;
+        rowData[nextColName] = null;
+      });
 
-        cols2.forEach(function (k) {
-          var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_y' : k;
-          rowData[nextColName] = df2.get(k).iloc(idx);
-        });
-        data.push(rowData);
-      })();
+      cols2.forEach(function (k) {
+        var nextColName = intersectCols.size > 0 && intersectCols.indexOf(k) >= 0 ? k + '_y' : k;
+        rowData[nextColName] = df2.get(k).iloc(idx);
+      });
+      data.push(rowData);
     }
   });
 
@@ -1245,4 +1188,46 @@ var mergeDataFrame = exports.mergeDataFrame = function mergeDataFrame(df1, df2,
     default:
       throw new Error('MergeError: ' + how + ' not a supported merge type');
   }
+};
+
+var _concatDataFrame = exports._concatDataFrame = function _concatDataFrame(objs, kwargs) {
+  if (!(objs instanceof _immutable2.default.List || Array.isArray(objs))) throw new Error('objs must be List or Array');
+
+  if (objs instanceof _immutable2.default.List && objs.filter(function (frame) {
+    return frame instanceof DataFrame;
+  }).size !== objs.size) throw new Error('Objects must all be DataFrame');else if (Array.isArray(objs) && objs.filter(function (frame) {
+    return frame instanceof DataFrame;
+  }).length !== objs.length) throw new Error('Objects must all be DataFrame');
+
+  if (Array.isArray(objs) && objs.length === 1) return objs[0];else if (objs instanceof _immutable2.default.List && objs.size === 1) return objs.get(0);
+
+  var seriesOrderedMap = _immutable2.default.OrderedMap({});
+  if (kwargs.axis === 1) {
+    objs.forEach(function (df) {
+      df.columns.forEach(function (column) {
+        var columnExists = seriesOrderedMap.has(column);
+        seriesOrderedMap = seriesOrderedMap.set(columnExists ? column + '.x' : column, columnExists ? df.get(column).rename(column + '.x') : df.get(column));
+      });
+    });
+  } else {
+    objs.forEach(function (df) {
+      var lenSeriesInMap = seriesOrderedMap.keySeq().size === 0 ? 0 : seriesOrderedMap.first().length;
+      var nextLength = df.length + lenSeriesInMap;
+
+      seriesOrderedMap = _immutable2.default.OrderedMap(seriesOrderedMap.entrySeq().map(function (_ref12) {
+        var _ref13 = (0, _slicedToArray3.default)(_ref12, 2),
+            column = _ref13[0],
+            series = _ref13[1];
+
+        if (df.columnExists(column)) return [column, (0, _series._concatSeries)([series, df.get(column)], kwargs)];
+        return [column, (0, _series._concatSeries)([series, new _series2.default(_immutable2.default.Repeat(NaN, df.length).toList(), { index: df.index })], kwargs)];
+      })).merge(_immutable2.default.OrderedMap(df.columns.filter(function (column) {
+        return !seriesOrderedMap.has(column);
+      }).map(function (column) {
+        return [column, lenSeriesInMap === 0 ? df.get(column) : (0, _series._concatSeries)([new _series2.default(_immutable2.default.Repeat(NaN, nextLength)), df.get(column)], kwargs)];
+      })));
+    });
+  }
+
+  return new DataFrame(seriesOrderedMap);
 };
\ No newline at end of file
diff --git a/dist/core/index.js b/dist/core/index.js
index 7295a1f..da5485f 100644
--- a/dist/core/index.js
+++ b/dist/core/index.js
@@ -22,4 +22,13 @@ Object.defineProperty(exports, 'DataFrame', {
   }
 });
 
+var _concat = require('./reshape/concat');
+
+Object.defineProperty(exports, 'concat', {
+  enumerable: true,
+  get: function get() {
+    return _interopRequireDefault(_concat).default;
+  }
+});
+
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
\ No newline at end of file
diff --git a/dist/core/reshape/concat.js b/dist/core/reshape/concat.js
new file mode 100644
index 0000000..f7dae02
--- /dev/null
+++ b/dist/core/reshape/concat.js
@@ -0,0 +1,28 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+var _immutable = require('immutable');
+
+var _immutable2 = _interopRequireDefault(_immutable);
+
+var _frame = require('../frame');
+
+var _frame2 = _interopRequireDefault(_frame);
+
+var _series = require('../series');
+
+var _series2 = _interopRequireDefault(_series);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+var concat = function concat(objs) {
+  var kwargs = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : { ignore_index: false, axis: 0 };
+
+  if (Array.isArray(objs) && objs[0] instanceof _series2.default || objs instanceof _immutable2.default.List && objs.get(0) instanceof _series2.default) return (0, _series._concatSeries)(objs, { ignore_index: kwargs.ignore_index });else if (Array.isArray(objs) && objs[0] instanceof _frame2.default || objs instanceof _immutable2.default.List && objs.get(0) instanceof _frame2.default) return (0, _frame._concatDataFrame)(objs, { ignore_index: kwargs.ignore_index, axis: kwargs.axis });
+  throw new Error('Not supported');
+};
+
+exports.default = concat;
\ No newline at end of file
diff --git a/dist/core/series.js b/dist/core/series.js
index 94fb26b..2e52b2a 100644
--- a/dist/core/series.js
+++ b/dist/core/series.js
@@ -3,6 +3,11 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
+exports._concatSeries = undefined;
+
+var _toConsumableArray2 = require('babel-runtime/helpers/toConsumableArray');
+
+var _toConsumableArray3 = _interopRequireDefault(_toConsumableArray2);
 
 var _slicedToArray2 = require('babel-runtime/helpers/slicedToArray');
 
@@ -98,9 +103,9 @@ var Series = function (_NDFrame) {
         for (var _iterator = (0, _utils.enumerate)(this)[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
           var _step$value = (0, _slicedToArray3.default)(_step.value, 2),
               val = _step$value[0],
-              idx = _step$value[1];
+              _idx = _step$value[1];
 
-          array.push(func(val, idx));
+          array.push(func(val, _idx));
         }
       } catch (err) {
         _didIteratorError = true;
@@ -238,74 +243,59 @@ var Series = function (_NDFrame) {
       }), { name: this.name, index: this.index });
     }
   }, {
-    key: 'add',
-    value: function add(val) {
-      if (typeof val === 'number') return this.map(function (v) {
-          return v + val;
-        });else if (val instanceof Series) return this.map(function (v, idx) {
-          return v + val.iloc(idx);
-        });else if (Array.isArray(val)) return this.map(function (v, idx) {
-        return v + val[idx];
-      });else if (val instanceof _immutable2.default.List) return this.map(function (v, idx) {
-          return v + val.get(idx);
-        });
+    key: '_combineOp',
+    value: function _combineOp(other, op) {
+      var opName = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : '';
+
+      if (typeof other === 'number') return this.map(function (val) {
+        return op(val, other);
+      });else if (other instanceof Series) return this.map(function (val, idx) {
+        return op(val, other.iloc(idx));
+      });else if (Array.isArray(other)) return this.map(function (val, idx) {
+        return op(val, other[idx]);
+      });else if (other instanceof _immutable2.default.List) return this.map(function (val, idx) {
+        return op(val, other.get(idx));
+      });
 
-      throw new Error('add only supports numbers, Arrays, Immutable List and pandas.Series');
+      throw new Error(opName + ' only supports numbers, Arrays, Immutable List and pandas.Series');
+    }
+  }, {
+    key: 'add',
+    value: function add(other) {
+      return this._combineOp(other, function (a, b) {
+        return a + b;
+      }, 'add');
     }
   }, {
     key: 'sub',
-    value: function sub(val) {
-      if (typeof val === 'number') return this.map(function (v) {
-          return v - val;
-        });else if (val instanceof Series) return this.map(function (v, idx) {
-          return v - val.iloc(idx);
-        });else if (Array.isArray(val)) return this.map(function (v, idx) {
-          return v - val[idx];
-        });else if (val instanceof _immutable2.default.List) return this.map(function (v, idx) {
-          return v - val.get(idx);
-        });
-
-      throw new Error('sub only supports numbers, Arrays, Immutable List and pandas.Series');
+    value: function sub(other) {
+      return this._combineOp(other, function (a, b) {
+        return a - b;
+      }, 'sub');
     }
   }, {
     key: 'mul',
-    value: function mul(val) {
-      if (typeof val === 'number') return this.map(function (v) {
-          return v * val;
-        });else if (val instanceof Series) return this.map(function (v, idx) {
-          return v * val.iloc(idx);
-        });else if (Array.isArray(val)) return this.map(function (v, idx) {
-          return v * val[idx];
-        });else if (val instanceof _immutable2.default.List) return this.map(function (v, idx) {
-          return v * val.get(idx);
-        });
-
-      throw new Error('mul only supports numbers, Arrays, Immutable List and pandas.Series');
+    value: function mul(other) {
+      return this._combineOp(other, function (a, b) {
+        return a * b;
+      });
     }
   }, {
     key: 'multiply',
-    value: function multiply(val) {
-      return this.mul(val);
+    value: function multiply(other) {
+      return this.mul(other);
     }
   }, {
     key: 'div',
-    value: function div(val) {
-      if (typeof val === 'number') return this.map(function (v) {
-          return v / val;
-        });else if (val instanceof Series) return this.map(function (v, idx) {
-          return v / val.iloc(idx);
-        });else if (Array.isArray(val)) return this.map(function (v, idx) {
-          return v / val[idx];
-        });else if (val instanceof _immutable2.default.List) return this.map(function (v, idx) {
-          return v / val.get(idx);
-        });
-
-      throw new Error('div only supports numbers, Arrays, Immutable List and pandas.Series');
+    value: function div(other) {
+      return this._combineOp(other, function (a, b) {
+        return a / b;
+      }, 'div');
     }
   }, {
     key: 'divide',
-    value: function divide(val) {
-      return this.div(val);
+    value: function divide(other) {
+      return this.div(other);
     }
   }, {
     key: 'cov',
@@ -632,6 +622,13 @@ var Series = function (_NDFrame) {
     value: function rename(name) {
       return new Series(this._values, { name: name, index: this.index });
     }
+  }, {
+    key: 'append',
+    value: function append(other) {
+      var ignore_index = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
+      return _concatSeries([this, other], { ignore_index: ignore_index });
+    }
   }, {
     key: 'kwargs',
     get: function get() {
@@ -672,4 +669,35 @@ var Series = function (_NDFrame) {
   return Series;
 }(_generic2.default);
 
-exports.default = Series;
\ No newline at end of file
+exports.default = Series;
+
+var _concatSeriesValues = function _concatSeriesValues(objs) {
+  var _Immutable$List;
+
+  return (_Immutable$List = _immutable2.default.List([])).concat.apply(_Immutable$List, (0, _toConsumableArray3.default)(objs.map(function (series) {
+    return series.values;
+  })));
+};
+var _concatSeriesIndices = function _concatSeriesIndices(objs) {
+  var _Immutable$List2;
+
+  return (_Immutable$List2 = _immutable2.default.List([])).concat.apply(_Immutable$List2, (0, _toConsumableArray3.default)(objs.map(function (series) {
+    return series.index;
+  })));
+};
+
+var _concatSeries = exports._concatSeries = function _concatSeries(objs, kwargs) {
+  if (objs instanceof _immutable2.default.List && objs.filter(function (series) {
+    return series instanceof Series;
+  }).size !== objs.size) throw new Error('Objects must all be Series');else if (Array.isArray(objs) && objs.filter(function (series) {
+    return series instanceof Series;
+  }).length !== objs.length) throw new Error('Objects must all be Series');
+
+  if (!kwargs.ignore_index) return new Series(_concatSeriesValues(objs), { index: _concatSeriesIndices(objs) });else if (kwargs.ignore_index) {
+    return new Series(_concatSeriesValues(objs), { index: _immutable2.default.Range(0, objs.reduce(function (a, b) {
+        return a + b.length;
+      }, 0)).toList() });
+  }
+
+  throw new Error('Not supported');
+};
\ No newline at end of file
diff --git a/dist/index.js b/dist/index.js
index c4d1524..3d5db18 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -18,6 +18,12 @@ Object.defineProperty(exports, 'DataFrame', {
     return _index.DataFrame;
   }
 });
+Object.defineProperty(exports, 'concat', {
+  enumerable: true,
+  get: function get() {
+    return _index.concat;
+  }
+});
 
 var _tools = require('./tseries/tools');
 
diff --git a/jest-config.json b/jest-config.json
deleted file mode 100644
index b64414b..0000000
--- a/jest-config.json
+++ /dev/null
@@ -1,16 +0,0 @@
-{
-  "modulePaths": [
-    "/shared/vendor/modules"
-  ],
-  "moduleFileExtensions": [
-    "js"
-  ],
-  "moduleDirectories": [
-    "node_modules",
-    "bower_components",
-    "shared"
-  ],
-  "roots": [
-    "src/js"
-  ]
-}
diff --git a/package-lock.json b/package-lock.json
index a86d3d0..ddd9950 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "pandas-js",
-  "version": "0.1.28",
+  "version": "0.2.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -3826,14 +3826,14 @@
       }
     },
     "eslint-plugin-react": {
-      "version": "7.1.0",
-      "resolved": "https://registry.npmjs.org/eslint-plugin-react/-/eslint-plugin-react-7.1.0.tgz",
-      "integrity": "sha1-J3cKzzn1/UnNCvQIPOWBBOs5DUw=",
+      "version": "7.2.0",
+      "resolved": "https://registry.npmjs.org/eslint-plugin-react/-/eslint-plugin-react-7.2.0.tgz",
+      "integrity": "sha512-GhgT80V8R3Xz/Rusosd/j7UuvSHakriJlcLHkAYaF0ENLUwFirWU3xCfBSbI5KdNURqHOhy7xtzZ4nC4npC3Kw==",
       "dev": true,
       "requires": {
         "doctrine": "2.0.0",
         "has": "1.0.1",
-        "jsx-ast-utils": "1.4.1"
+        "jsx-ast-utils": "2.0.0"
       },
       "dependencies": {
         "doctrine": {
@@ -3847,10 +3847,13 @@
           }
         },
         "jsx-ast-utils": {
-          "version": "1.4.1",
-          "resolved": "https://registry.npmjs.org/jsx-ast-utils/-/jsx-ast-utils-1.4.1.tgz",
-          "integrity": "sha1-OGchPo3Xm/Ho8jAMDPwe+xgsDfE=",
-          "dev": true
+          "version": "2.0.0",
+          "resolved": "https://registry.npmjs.org/jsx-ast-utils/-/jsx-ast-utils-2.0.0.tgz",
+          "integrity": "sha1-7Aaj1gzzB+XhGdrHutgeifCW8Pg=",
+          "dev": true,
+          "requires": {
+            "array-includes": "3.0.3"
+          }
         }
       }
     },
diff --git a/package.json b/package.json
index 1469fa3..b4e2878 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "pandas-js",
-  "version": "0.1.28",
+  "version": "0.2.0",
   "description": "Pandas for JavaScript",
   "author": "StratoDem Analytics tech@stratodem.com",
   "contributors": [
@@ -36,7 +36,7 @@
     "eslint-plugin-flowtype": "^2.35.0",
     "eslint-plugin-import": "^2.7.0",
     "eslint-plugin-jsx-a11y": "^6.0.2",
-    "eslint-plugin-react": "^7.1.0",
+    "eslint-plugin-react": "^7.2.0",
     "flow-bin": "^0.52.0",
     "flow-remove-types": "^1.2.1",
     "jest": "^20.0.4",
@@ -51,7 +51,8 @@
   },
   "jest": {
     "modulePaths": [
-      "/shared/vendor/modules"
+      "/shared/vendor/modules",
+      "<rootDir>/src/es6"
     ],
     "moduleFileExtensions": [
       "js"
diff --git a/src/es6/__tests__/core/frame.js b/src/es6/__tests__/core/frame.js
index be398ec..59a882e 100644
--- a/src/es6/__tests__/core/frame.js
+++ b/src/es6/__tests__/core/frame.js
@@ -981,25 +981,25 @@ describe('frame', () => {
       expect(df2.index.toArray()).toEqual([1, 2, 3]);
     });
   });
-
-  describe('pivot_table', () => {
-    it('pivots', () => {
-      const df = new DataFrame([
-        {a: 1, b: 1, c: 1, d: 3},
-        // {a: 1, b: 1, c: 1, d: 4},
-        {a: 1, b: 1, c: 2, d: 8},
-        {a: 1, b: 2, c: 1, d: 9},
-        {a: 1, b: 2, c: 2, d: 10},
-        {a: 2, b: 1, c: 1, d: 1},
-        {a: 2, b: 1, c: 2, d: 4},
-        {a: 2, b: 2, c: 1, d: 1},
-        {a: 2, b: 2, c: 2, d: 3},
-        {a: 2, b: 2, c: 2, d: 3},
-      ]);
-
-      console.log(df.pivot_table(['a', 'b'], 'c', 'd'));
-    });
-  });
+  //
+  // describe('pivot_table', () => {
+  //   it('pivots', () => {
+  //     const df = new DataFrame([
+  //       {a: 1, b: 1, c: 1, d: 3},
+  //       // {a: 1, b: 1, c: 1, d: 4},
+  //       {a: 1, b: 1, c: 2, d: 8},
+  //       {a: 1, b: 2, c: 1, d: 9},
+  //       {a: 1, b: 2, c: 2, d: 10},
+  //       {a: 2, b: 1, c: 1, d: 1},
+  //       {a: 2, b: 1, c: 2, d: 4},
+  //       {a: 2, b: 2, c: 1, d: 1},
+  //       {a: 2, b: 2, c: 2, d: 3},
+  //       {a: 2, b: 2, c: 2, d: 3},
+  //     ]);
+  //
+  //     console.log(df.pivot_table(['a', 'b'], 'c', 'd'));
+  //   });
+  // });
 
   describe('rename', () => {
     it('renames one Series in the DataFrame', () => {
@@ -1029,4 +1029,58 @@ describe('frame', () => {
       expect(df.length).toEqual(5);
     });
   });
+
+  describe('append', () => {
+    it('Appends a DataFrame to another when ignore_index is false', () => {
+      const df1 = new DataFrame(
+        [{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+      const df2 = new DataFrame(
+        [{x: 2, y: 2}, {x: 3, y: 3}, {x: 4, y: 4}], {index: [2, 3, 4]});
+
+      const df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a DataFrame to another when ignore_index is true', () => {
+      const df1 = new DataFrame(
+        [{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+      const df2 = new DataFrame(
+        [{x: 2, y: 2}, {x: 3, y: 3}, {x: 4, y: 4}], {index: [2, 3, 4]});
+
+      const df3 = df1.append(df2, true);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Appends an empty DataFrame to another', () => {
+      const df1 = new DataFrame(
+        [{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+      const df2 = new DataFrame([]);
+
+      const df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
+
+  describe('transpose', () => {
+    it('Tranposes a DataFrame by flipping indexes and columns', () => {
+      const df1 = new DataFrame(
+        [{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+      const df2 = df1.transpose();
+
+      expect(df2.columns.toArray()).toEqual([1, 2, 3]);
+      expect(df2.index.toArray()).toEqual(['x', 'y']);
+      expect(df2.get(1).index.toArray()).toEqual(['x', 'y']);
+
+      const df3 = df2.transpose();
+      expect(df3.columns.toArray()).toEqual(['x', 'y']);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('x').index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
 });
diff --git a/src/es6/__tests__/core/reshape/concat.js b/src/es6/__tests__/core/reshape/concat.js
new file mode 100644
index 0000000..82c67dc
--- /dev/null
+++ b/src/es6/__tests__/core/reshape/concat.js
@@ -0,0 +1,79 @@
+/** @flow
+ * StratoDem Analytics : concat
+ * Principal Author(s) : Michael Clawar
+ * Secondary Author(s) :
+ * Description :
+ *
+ *  (c) 2016- StratoDem Analytics, LLC
+ *  All Rights Reserved
+ */
+
+import Immutable from 'immutable';
+import DataFrame from '../../../core/frame';
+import Series from '../../../core/series';
+
+import concat from '../../../core/reshape/concat';
+
+describe('concat', () => {
+  describe('concat Series', () => {
+    it('Concatenates two Series without ignoring index', () => {
+      const series1 = new Series([1, 2, 3, 4]);
+      const series2 = new Series([2, 3, 4, 5]);
+
+      const series3 = concat([series1, series2]);
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 0, 1, 2, 3]);
+    });
+
+    it('Concatenates two Series with ignore index', () => {
+      const series1 = new Series([1, 2, 3, 4]);
+      const series2 = new Series([2, 3, 4, 5]);
+
+      const series3 = concat([series1, series2], {ignore_index: true});
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5, 6, 7]);
+    });
+
+    it('Throws an error if the first object in concat is a Series '
+      + 'and any of the rest are not', () => {
+      const series1 = new Series([1, 2, 3, 4]);
+      const series2 = new Series([2, 3, 4, 5]);
+
+      expect(() => concat([series1, series2, []], {ignore_index: true})).toThrow();
+      expect(() => concat(Immutable.List([series1, series2, []]), {ignore_index: true})).toThrow();
+    });
+  });
+
+  describe('concat DataFrame', () => {
+    it('Concatenates two DataFrames without ignoring index', () => {
+      const frame1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}]);
+      const frame2 = new DataFrame([{x: 2, y: 3}, {x: 3, y: 4}, {x: 4, y: 5}]);
+
+      const frame3 = concat([frame1, frame2]);
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 0, 1, 2]);
+    });
+
+    it('Concatenates two DataFrames with index ignored', () => {
+      const frame1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}]);
+      const frame2 = new DataFrame([{x: 2, y: 3}, {x: 3, y: 4}, {x: 4, y: 5}]);
+
+      const frame3 = concat([frame1, frame2], {ignore_index: true});
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Concatenates two DataFrames along axis = 1 without ignoring index', () => {
+      const frame1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}]);
+      const frame2 = new DataFrame([{x: 2, y: 3}, {x: 3, y: 4}, {x: 4, y: 5}]);
+
+      const frame3 = concat([frame1, frame2], {axis: 1});
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(frame3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').name).toEqual('x.x');
+      expect(frame3.get('y.x').values.toArray()).toEqual([3, 4, 5]);
+      expect(frame3.get('y.x').name).toEqual('y.x');
+    });
+  });
+});
diff --git a/src/es6/__tests__/core/series.js b/src/es6/__tests__/core/series.js
index 732237f..8dd58ba 100644
--- a/src/es6/__tests__/core/series.js
+++ b/src/es6/__tests__/core/series.js
@@ -629,4 +629,22 @@ describe('series', () => {
       });
     });
   });
+
+  describe('append', () => {
+    it('Appends a Series to another when ignore_index is false', () => {
+      const ds1 = new Series([1, 2, 3], {index: [1, 2, 3]});
+      const ds2 = new Series([2, 3, 4], {index: [2, 3, 4]});
+      const ds3 = ds1.append(ds2);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a Series to another when ignore_index is true', () => {
+      const ds1 = new Series([1, 2, 3], {index: [1, 2, 3]});
+      const ds2 = new Series([2, 3, 4], {index: [2, 3, 4]});
+      const ds3 = ds1.append(ds2, true);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+  });
 });
diff --git a/src/es6/core/frame.js b/src/es6/core/frame.js
index 5abac5b..62f3e20 100644
--- a/src/es6/core/frame.js
+++ b/src/es6/core/frame.js
@@ -9,10 +9,11 @@ import Immutable from 'immutable';
 import { InvalidAxisError } from './exceptions';
 import NDFrame from './generic';
 import { MultiIndex } from './multiindex';
-import Series from './series';
+import Series, { _concatSeries } from './series';
 // import { Workbook, Sheet } from './structs'; TODO
 import { enumerate, nonMergeColumns, intersectingColumns, parseIndex,
   OP_CUMSUM, OP_CUMMUL, OP_CUMMIN, OP_CUMMAX, generateCumulativeFunc } from './utils';
+import concat from './reshape/concat';
 
 
 declare type T_LIST = Immutable.List
@@ -1571,6 +1572,57 @@ export default class DataFrame extends NDFrame {
       return [nextCol, this._data.get(prevCol).rename(nextCol)];
     })), {index: this.index});
   }
+
+  /**
+   * Append another DataFrame to this and return a new DataFrame
+   *
+   * pandas equivalent: [DataFrame.append](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.append.html)
+   *
+   * @param {DataFrame} other
+   * @param {boolean} ignore_index
+   * @returns {DataFrame}
+   *
+   * @example
+   * const df1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}], {index: [1, 2]});
+   * const df2 = new DataFrame([{x: 2, y: 2}, {x: 3, y: 3}], {index: [2, 3]});
+   *
+   * // Returns DataFrame(
+   *   [{x: 1, y: 2}, {x: 2, y: 3}, {x: 2, y: 2}, {x: 3, y: 3}],
+   *   {index: [1, 2, 2, 3]});
+   * df1.append(df2);
+   *
+   * // Returns DataFrame(
+   *   [{x: 1, y: 2}, {x: 2, y: 3}, {x: 2, y: 2}, {x: 3, y: 3}],
+   *   {index: [0, 1, 2, 3]});
+   * df1.append(df2, true);
+   */
+  append(other: DataFrame, ignore_index: boolean = false): DataFrame {
+    // eslint-disable-next-line
+    return _concatDataFrame(// $FlowIssue
+      [this, other],
+      {ignore_index});
+  }
+
+  /**
+   * Transpose the DataFrame by switching the index and columns
+   *
+   * pandas equivalent: [DataFrame.transpose](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.transpose.html)
+   *
+   * @returns {DataFrame}
+   *
+   * @example
+   * const df1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+   *
+   * // Returns DataFrame(
+   *   [{1: 1, 2: 2, 3: 3}, {1: 2, 2: 3, 3: 4}], {index: ['x', 'y']});
+   * df1.transpose();
+   */
+  transpose(): DataFrame {
+    return new DataFrame(
+      Immutable.OrderedMap(
+        this.index.map((index, idx) =>
+          ([index, new Series(this.values.get(idx), {index: this.columns.toList()})]))));
+  }
 }
 
 const innerMerge = (df1: DataFrame, df2: DataFrame, on: Array<string | number>): DataFrame => {
@@ -1750,3 +1802,66 @@ export const mergeDataFrame = (df1: DataFrame, df2: DataFrame, on: Array<string
       throw new Error(`MergeError: ${how} not a supported merge type`);
   }
 };
+
+// Concat
+type T_KWARGS = {ignore_index: boolean, axis?: 0 | 1};
+export const _concatDataFrame = (objs: Array<DataFrame> | Immutable.List<DataFrame>,
+                                 kwargs: T_KWARGS): DataFrame => {
+  if (!(objs instanceof Immutable.List || Array.isArray(objs)))
+    throw new Error('objs must be List or Array');
+
+  if (objs instanceof Immutable.List
+    && objs.filter(frame => frame instanceof DataFrame).size !== objs.size)
+    throw new Error('Objects must all be DataFrame');
+  else if (Array.isArray(objs)
+    && objs.filter(frame => frame instanceof DataFrame).length !== objs.length)
+    throw new Error('Objects must all be DataFrame');
+
+  if (Array.isArray(objs) && objs.length === 1)
+    return objs[0];
+  else if (objs instanceof Immutable.List && objs.size === 1)
+    return objs.get(0);
+
+  let seriesOrderedMap = Immutable.OrderedMap({});
+  if (kwargs.axis === 1) {
+    objs.forEach((df: DataFrame) => {
+      df.columns.forEach((column: string) => {
+        const columnExists = seriesOrderedMap.has(column);
+        seriesOrderedMap = seriesOrderedMap.set(
+          columnExists ? `${column}.x` : column, // $FlowIssue
+          columnExists ? df.get(column).rename(`${column}.x`) : df.get(column));
+      });
+    });
+  } else {
+    objs.forEach((df: DataFrame) => {
+      const lenSeriesInMap = seriesOrderedMap.keySeq().size === 0
+        ? 0
+        : seriesOrderedMap.first().length;
+      const nextLength = df.length + lenSeriesInMap;
+
+      seriesOrderedMap = Immutable.OrderedMap(
+        // Get entries already concated (already in seriesOrderedMap)
+        seriesOrderedMap.entrySeq().map(([column, series]) => {
+          if (df.columnExists(column))
+            return [
+              column, // $FlowIssue
+              _concatSeries([series, df.get(column)], kwargs)];
+          return [
+            column, // $FlowIssue
+            _concatSeries([
+              series,
+              new Series(Immutable.Repeat(NaN, df.length).toList(), {index: df.index})],
+            kwargs)]; // Now merge with columns only in the "right" DataFrame
+        })).merge(Immutable.OrderedMap(
+        df.columns
+          .filter(column => !seriesOrderedMap.has(column))
+          .map(column => // $FlowIssue
+            ([column, lenSeriesInMap === 0 ? df.get(column) : _concatSeries([
+              new Series(Immutable.Repeat(NaN, nextLength)),
+              df.get(column)],
+            kwargs)]))));
+    });
+  }
+
+  return new DataFrame(seriesOrderedMap);
+};
diff --git a/src/es6/core/index.js b/src/es6/core/index.js
index cf294be..0740604 100644
--- a/src/es6/core/index.js
+++ b/src/es6/core/index.js
@@ -13,3 +13,4 @@
 
 export { default as Series } from './series';
 export { default as DataFrame } from './frame';
+export { default as concat } from './reshape/concat';
\ No newline at end of file
diff --git a/src/es6/core/reshape/concat.js b/src/es6/core/reshape/concat.js
new file mode 100644
index 0000000..33657ba
--- /dev/null
+++ b/src/es6/core/reshape/concat.js
@@ -0,0 +1,51 @@
+/** @flow
+ * StratoDem Analytics : concat.js
+ * Principal Author(s) : Michael Clawar
+ * Secondary Author(s) :
+ * Description :
+ *
+ *  (c) 2016- StratoDem Analytics, LLC
+ *  All Rights Reserved
+ */
+
+import Immutable from 'immutable';
+
+import DataFrame, { _concatDataFrame } from '../frame';
+import Series, { _concatSeries } from '../series';
+
+type T_CONCAT = DataFrame | Series;
+type T_OBJS = Array<T_CONCAT> | Immutable.List<T_CONCAT>;
+
+type T_KWARGS = {
+  ignore_index: boolean,
+  axis?: 0 | 1,
+}
+
+/**
+ * Concatenate pandas objects along a particular axis.
+ *
+ * pandas equivalent: [pandas.concat](https://pandas.pydata.org/pandas-docs/stable/generated/pandas.concat.html)
+ *
+ * @returns {Series | DataFrame}
+ *
+ * @example
+ * const series1 = new Series([1, 2, 3, 4]);
+ * const series2 = new Series([2, 3, 4, 5]);
+ *
+ * // Returns Series([1, 2, 3, 4, 2, 3, 4, 5], {index: [0, 1, 2, 3, 0, 1, 2, 3]})
+ * concat([series1, series2], {ignore_index: false});
+ *
+ * // Returns Series([1, 2, 3, 4, 2, 3, 4, 5], {index: [0, 1, 2, 3, 4, 5, 6, 7]})
+ * concat([series1, series2], {ignore_index: true});
+ */
+const concat = (objs: T_OBJS, kwargs: T_KWARGS = {ignore_index: false, axis: 0}): T_CONCAT => {
+  if ((Array.isArray(objs) && objs[0] instanceof Series)
+      || (objs instanceof Immutable.List && objs.get(0) instanceof Series))
+    return _concatSeries(objs, {ignore_index: kwargs.ignore_index});
+  else if ((Array.isArray(objs) && objs[0] instanceof DataFrame)
+    || (objs instanceof Immutable.List && objs.get(0) instanceof DataFrame))
+    return _concatDataFrame(objs, {ignore_index: kwargs.ignore_index, axis: kwargs.axis});
+  throw new Error('Not supported');
+};
+
+export default concat;
diff --git a/src/es6/core/series.js b/src/es6/core/series.js
index a4dff05..30cf3d7 100644
--- a/src/es6/core/series.js
+++ b/src/es6/core/series.js
@@ -11,7 +11,6 @@ import {enumerate, sum, parseIndex, round10,
   OP_CUMSUM, OP_CUMMUL, OP_CUMMAX, OP_CUMMIN, generateCumulativeFunc} from './utils';
 import {DType, arrayToDType} from './dtype';
 
-
 declare type T_MF = (value: number, idx: number) => number | string;
 declare type T_BF = (value1: number, value2: number) => boolean;
 
@@ -42,7 +41,7 @@ export default class Series extends NDFrame {
    * // 5  4
    * // Name: My test name, dtype: dtype(int)
    */
-  constructor(data: Array<Object>|Object, kwargs: Object = {}) {
+  constructor(data: Array<Object> | Object, kwargs: Object = {}) {
     super(data, kwargs);
 
     if (Array.isArray(data)) {
@@ -98,6 +97,7 @@ export default class Series extends NDFrame {
    */
   map(func: T_MF): Series {
     const array = [];
+    // eslint-disable-next-line
     for (const [val, idx] of enumerate(this)) {
       // $FlowIssue TODO
       array.push(func(val, idx));
@@ -246,7 +246,7 @@ export default class Series extends NDFrame {
    * // Returns List [1, 2, 3]
    * ds.index;
    */
-  set index(index: Immutable.List|Array<number|string>) {
+  set index(index: Immutable.List | Array<number | string>) {
     this.set_axis(0, parseIndex(index, this.values));
   }
 
@@ -719,7 +719,7 @@ export default class Series extends NDFrame {
     return new Series(
       Immutable.Repeat(null, periods).toList().concat(
         Immutable.Range(periods, this.length).map(idx =>
-        (this.values.get(idx) - this.values.get(idx - periods))).toList()),
+          (this.values.get(idx) - this.values.get(idx - periods))).toList()),
       {index: this.index, name: this.name});
   }
 
@@ -748,7 +748,7 @@ export default class Series extends NDFrame {
     return new Series(
       Immutable.Repeat(null, periods).toList().concat(
         Immutable.Range(periods, this.length).map(idx =>
-        (this.values.get(idx) / this.values.get(idx - periods)) - 1).toList()),
+          (this.values.get(idx) / this.values.get(idx - periods)) - 1).toList()),
       {index: this.index, name: this.name});
   }
 
@@ -1136,7 +1136,7 @@ export default class Series extends NDFrame {
    * // Returns Series([2, 3]);
    * ds.filter(ds.gte(2));
    */
-  filter(iterBool: Series|Array<boolean>|Immutable.List): Series {
+  filter(iterBool: Series | Array<boolean> | Immutable.List): Series {
     if (!Array.isArray(iterBool)
       && !(iterBool instanceof Immutable.List)
       && !(iterBool instanceof Series))
@@ -1233,7 +1233,7 @@ export default class Series extends NDFrame {
   cummin(): Series {
     return this._cumulativeHelper(OP_CUMMIN);
   }
-  
+
   /**
    * Convert the Series to a json object
    *
@@ -1300,4 +1300,58 @@ export default class Series extends NDFrame {
   rename(name: string | number): Series {
     return new Series(this._values, {name, index: this.index});
   }
+
+  /**
+   * Append another Series to this and return a new Series
+   *
+   * pandas equivalent: [Series.append](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.append.html)
+   *
+   * @param {Series} other
+   * @param {boolean} ignore_index
+   * @returns {Series}
+   *
+   * @example
+   * const ds1 = new Series([1, 2, 3], {index: [1, 2, 3]});
+   * const ds2 = new Series([2, 3, 4], {index: [3, 4, 5]});
+   *
+   * // Returns Series([1, 2, 3, 2, 3, 4], {index: [1, 2, 3, 3, 4, 5]});
+   * ds1.append(ds2);
+   *
+   * // Returns Series([1, 2, 3, 2, 3, 4], {index: [0, 1, 2, 3, 4, 5]});
+   * ds1.append(ds2, true);
+   */
+  append(other: Series, ignore_index: boolean = false): Series {
+    // eslint-disable-next-line
+    return _concatSeries( // $FlowIssue
+      [this, other],
+      {ignore_index});
+  }
 }
+
+
+type T_ITER_SERIES = Array<Series> | Immutable.List<Series>;
+type T_KWARGS = {ignore_index: boolean, axis?: 0 | 1};
+const _concatSeriesValues = (objs: T_ITER_SERIES) =>
+  Immutable.List([]).concat(...objs.map(series => series.values));
+const _concatSeriesIndices = (objs: T_ITER_SERIES) =>
+  Immutable.List([]).concat(...objs.map(series => series.index));
+
+export const _concatSeries = (objs: Array<Series> | Immutable.List<Series>,
+                              kwargs: T_KWARGS): Series => {
+  if (objs instanceof Immutable.List
+    && objs.filter(series => series instanceof Series).size !== objs.size)
+    throw new Error('Objects must all be Series');
+  else if (Array.isArray(objs)
+    && objs.filter(series => series instanceof Series).length !== objs.length)
+    throw new Error('Objects must all be Series');
+
+  if (!kwargs.ignore_index)
+    return new Series(_concatSeriesValues(objs), {index: _concatSeriesIndices(objs)});
+  else if (kwargs.ignore_index) {
+    return new Series(
+      _concatSeriesValues(objs),
+      {index: Immutable.Range(0, objs.reduce((a, b: Series) => a + b.length, 0)).toList()});
+  }
+
+  throw new Error('Not supported');
+};
diff --git a/src/es6/index.js b/src/es6/index.js
index e3059d2..7579d46 100644
--- a/src/es6/index.js
+++ b/src/es6/index.js
@@ -1,3 +1,3 @@
 
-export { Series, DataFrame } from './core/index';
+export { Series, DataFrame, concat } from './core/index';
 export { to_datetime } from './tseries/tools';
diff --git a/src/js/__tests__/core/frame.js b/src/js/__tests__/core/frame.js
index 539f6cb..cf2e5b2 100644
--- a/src/js/__tests__/core/frame.js
+++ b/src/js/__tests__/core/frame.js
@@ -989,16 +989,25 @@ describe('frame', function () {
       expect(df2.index.toArray()).toEqual([1, 2, 3]);
     });
   });
-
-  describe('pivot_table', function () {
-    it('pivots', function () {
-      var df = new _frame2.default([{ a: 1, b: 1, c: 1, d: 3 },
-      // {a: 1, b: 1, c: 1, d: 4},
-      { a: 1, b: 1, c: 2, d: 8 }, { a: 1, b: 2, c: 1, d: 9 }, { a: 1, b: 2, c: 2, d: 10 }, { a: 2, b: 1, c: 1, d: 1 }, { a: 2, b: 1, c: 2, d: 4 }, { a: 2, b: 2, c: 1, d: 1 }, { a: 2, b: 2, c: 2, d: 3 }, { a: 2, b: 2, c: 2, d: 3 }]);
-
-      console.log(df.pivot_table(['a', 'b'], 'c', 'd'));
-    });
-  });
+  //
+  // describe('pivot_table', () => {
+  //   it('pivots', () => {
+  //     const df = new DataFrame([
+  //       {a: 1, b: 1, c: 1, d: 3},
+  //       // {a: 1, b: 1, c: 1, d: 4},
+  //       {a: 1, b: 1, c: 2, d: 8},
+  //       {a: 1, b: 2, c: 1, d: 9},
+  //       {a: 1, b: 2, c: 2, d: 10},
+  //       {a: 2, b: 1, c: 1, d: 1},
+  //       {a: 2, b: 1, c: 2, d: 4},
+  //       {a: 2, b: 2, c: 1, d: 1},
+  //       {a: 2, b: 2, c: 2, d: 3},
+  //       {a: 2, b: 2, c: 2, d: 3},
+  //     ]);
+  //
+  //     console.log(df.pivot_table(['a', 'b'], 'c', 'd'));
+  //   });
+  // });
 
   describe('rename', function () {
     it('renames one Series in the DataFrame', function () {
@@ -1027,6 +1036,54 @@ describe('frame', function () {
       expect(df.length).toEqual(5);
     });
   });
+
+  describe('append', function () {
+    it('Appends a DataFrame to another when ignore_index is false', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([{ x: 2, y: 2 }, { x: 3, y: 3 }, { x: 4, y: 4 }], { index: [2, 3, 4] });
+
+      var df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a DataFrame to another when ignore_index is true', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([{ x: 2, y: 2 }, { x: 3, y: 3 }, { x: 4, y: 4 }], { index: [2, 3, 4] });
+
+      var df3 = df1.append(df2, true);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4, 2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Appends an empty DataFrame to another', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = new _frame2.default([]);
+
+      var df3 = df1.append(df2);
+      expect(df3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
+
+  describe('transpose', function () {
+    it('Tranposes a DataFrame by flipping indexes and columns', function () {
+      var df1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }], { index: [1, 2, 3] });
+      var df2 = df1.transpose();
+
+      expect(df2.columns.toArray()).toEqual([1, 2, 3]);
+      expect(df2.index.toArray()).toEqual(['x', 'y']);
+      expect(df2.get(1).index.toArray()).toEqual(['x', 'y']);
+
+      var df3 = df2.transpose();
+      expect(df3.columns.toArray()).toEqual(['x', 'y']);
+      expect(df3.index.toArray()).toEqual([1, 2, 3]);
+      expect(df3.get('x').index.toArray()).toEqual([1, 2, 3]);
+    });
+  });
 });
 
 //# sourceMappingURL=frame.js.map
\ No newline at end of file
diff --git a/src/js/__tests__/core/reshape/concat.js b/src/js/__tests__/core/reshape/concat.js
new file mode 100644
index 0000000..7ecb74c
--- /dev/null
+++ b/src/js/__tests__/core/reshape/concat.js
@@ -0,0 +1,98 @@
+'use strict';
+
+var _immutable = require('immutable');
+
+var _immutable2 = _interopRequireDefault(_immutable);
+
+var _frame = require('../../../core/frame');
+
+var _frame2 = _interopRequireDefault(_frame);
+
+var _series = require('../../../core/series');
+
+var _series2 = _interopRequireDefault(_series);
+
+var _concat = require('../../../core/reshape/concat');
+
+var _concat2 = _interopRequireDefault(_concat);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/** 
+ * StratoDem Analytics : concat
+ * Principal Author(s) : Michael Clawar
+ * Secondary Author(s) :
+ * Description :
+ *
+ *  (c) 2016- StratoDem Analytics, LLC
+ *  All Rights Reserved
+ */
+
+describe('concat', function () {
+  describe('concat Series', function () {
+    it('Concatenates two Series without ignoring index', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      var series3 = (0, _concat2.default)([series1, series2]);
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 0, 1, 2, 3]);
+    });
+
+    it('Concatenates two Series with ignore index', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      var series3 = (0, _concat2.default)([series1, series2], { ignore_index: true });
+      expect(series3.values.toArray()).toEqual([1, 2, 3, 4, 2, 3, 4, 5]);
+      expect(series3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5, 6, 7]);
+    });
+
+    it('Throws an error if the first object in concat is a Series ' + 'and any of the rest are not', function () {
+      var series1 = new _series2.default([1, 2, 3, 4]);
+      var series2 = new _series2.default([2, 3, 4, 5]);
+
+      expect(function () {
+        return (0, _concat2.default)([series1, series2, []], { ignore_index: true });
+      }).toThrow();
+      expect(function () {
+        return (0, _concat2.default)(_immutable2.default.List([series1, series2, []]), { ignore_index: true });
+      }).toThrow();
+    });
+  });
+
+  describe('concat DataFrame', function () {
+    it('Concatenates two DataFrames without ignoring index', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2]);
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 0, 1, 2]);
+    });
+
+    it('Concatenates two DataFrames with index ignored', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2], { ignore_index: true });
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(frame3.get('x').index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+
+    it('Concatenates two DataFrames along axis = 1 without ignoring index', function () {
+      var frame1 = new _frame2.default([{ x: 1, y: 2 }, { x: 2, y: 3 }, { x: 3, y: 4 }]);
+      var frame2 = new _frame2.default([{ x: 2, y: 3 }, { x: 3, y: 4 }, { x: 4, y: 5 }]);
+
+      var frame3 = (0, _concat2.default)([frame1, frame2], { axis: 1 });
+      expect(frame3.get('x').values.toArray()).toEqual([1, 2, 3]);
+      expect(frame3.get('y').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').values.toArray()).toEqual([2, 3, 4]);
+      expect(frame3.get('x.x').name).toEqual('x.x');
+      expect(frame3.get('y.x').values.toArray()).toEqual([3, 4, 5]);
+      expect(frame3.get('y.x').name).toEqual('y.x');
+    });
+  });
+});
+
+//# sourceMappingURL=concat.js.map
\ No newline at end of file
diff --git a/src/js/__tests__/core/series.js b/src/js/__tests__/core/series.js
index e139ce6..de69864 100644
--- a/src/js/__tests__/core/series.js
+++ b/src/js/__tests__/core/series.js
@@ -658,6 +658,24 @@ describe('series', function () {
       });
     });
   });
+
+  describe('append', function () {
+    it('Appends a Series to another when ignore_index is false', function () {
+      var ds1 = new _series2.default([1, 2, 3], { index: [1, 2, 3] });
+      var ds2 = new _series2.default([2, 3, 4], { index: [2, 3, 4] });
+      var ds3 = ds1.append(ds2);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+    });
+
+    it('Appends a Series to another when ignore_index is true', function () {
+      var ds1 = new _series2.default([1, 2, 3], { index: [1, 2, 3] });
+      var ds2 = new _series2.default([2, 3, 4], { index: [2, 3, 4] });
+      var ds3 = ds1.append(ds2, true);
+      expect(ds3.values.toArray()).toEqual([1, 2, 3, 2, 3, 4]);
+      expect(ds3.index.toArray()).toEqual([0, 1, 2, 3, 4, 5]);
+    });
+  });
 });
 
 //# sourceMappingURL=series.js.map
\ No newline at end of file
diff --git a/src/js/core/frame.js b/src/js/core/frame.js
index 70cc423..fa29e59 100644
--- a/src/js/core/frame.js
+++ b/src/js/core/frame.js
@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.mergeDataFrame = undefined;
+exports._concatDataFrame = exports.mergeDataFrame = undefined;
 
 var _toConsumableArray2 = require('babel-runtime/helpers/toConsumableArray');
 
@@ -55,13 +55,17 @@ var _series2 = _interopRequireDefault(_series);
 
 var _utils = require('./utils');
 
+var _concat = require('./reshape/concat');
+
+var _concat2 = _interopRequireDefault(_concat);
+
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
 // eslint-disable-next-line
 
-/**
- * DataFrame object
- */
+// import { Workbook, Sheet } from './structs'; TODO
+
+// import { saveAs } from 'file-saver'; TODO figure out if best way
 
 var parseArrayToSeriesMap = function parseArrayToSeriesMap(array, index) {
   var dataMap = _immutable2.default.Map({});
@@ -92,9 +96,9 @@ var parseArrayToSeriesMap = function parseArrayToSeriesMap(array, index) {
 
   return _immutable2.default.Map(dataMap);
 };
-// import { Workbook, Sheet } from './structs'; TODO
-
-// import { saveAs } from 'file-saver'; TODO figure out if best way
+/**
+ * DataFrame object
+ */
 
 var DataFrame = function (_NDFrame) {
   (0, _inherits3.default)(DataFrame, _NDFrame);
@@ -1653,6 +1657,65 @@ var DataFrame = function (_NDFrame) {
         return [nextCol, _this17._data.get(prevCol).rename(nextCol)];
       })), { index: this.index });
     }
+
+    /**
+     * Append another DataFrame to this and return a new DataFrame
+     *
+     * pandas equivalent: [DataFrame.append](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.append.html)
+     *
+     * @param {DataFrame} other
+     * @param {boolean} ignore_index
+     * @returns {DataFrame}
+     *
+     * @example
+     * const df1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}], {index: [1, 2]});
+     * const df2 = new DataFrame([{x: 2, y: 2}, {x: 3, y: 3}], {index: [2, 3]});
+     *
+     * // Returns DataFrame(
+     *   [{x: 1, y: 2}, {x: 2, y: 3}, {x: 2, y: 2}, {x: 3, y: 3}],
+     *   {index: [1, 2, 2, 3]});
+     * df1.append(df2);
+     *
+     * // Returns DataFrame(
+     *   [{x: 1, y: 2}, {x: 2, y: 3}, {x: 2, y: 2}, {x: 3, y: 3}],
+     *   {index: [0, 1, 2, 3]});
+     * df1.append(df2, true);
+     */
+
+  }, {
+    key: 'append',
+    value: function append(other) {
+      var ignore_index = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
+      // eslint-disable-next-line
+      return _concatDataFrame( // $FlowIssue
+      [this, other], { ignore_index: ignore_index });
+    }
+
+    /**
+     * Transpose the DataFrame by switching the index and columns
+     *
+     * pandas equivalent: [DataFrame.transpose](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.transpose.html)
+     *
+     * @returns {DataFrame}
+     *
+     * @example
+     * const df1 = new DataFrame([{x: 1, y: 2}, {x: 2, y: 3}, {x: 3, y: 4}], {index: [1, 2, 3]});
+     *
+     * // Returns DataFrame(
+     *   [{1: 1, 2: 2, 3: 3}, {1: 2, 2: 3, 3: 4}], {index: ['x', 'y']});
+     * df1.transpose();
+     */
+
+  }, {
+    key: 'transpose',
+    value: function transpose() {
+      var _this18 = this;
+
+      return new DataFrame(_immutable2.default.OrderedMap(this.index.map(function (index, idx) {
+        return [index, new _series2.default(_this18.values.get(idx), { index: _this18.columns.toList() })];
+      })));
+    }
   }, {
     key: 'kwargs',
     get: function get() {
@@ -1676,15 +1739,15 @@ var DataFrame = function (_NDFrame) {
   }, {
     key: 'values',
     get: function get() {
-      var _this18 = this;
+      var _this19 = this;
 
       if (this._values instanceof _immutable2.default.List) return (0, _get3.default)(DataFrame.prototype.__proto__ || Object.getPrototypeOf(DataFrame.prototype), 'values', this);
 
       var valuesList = _immutable2.default.List([]);
 
       var _loop = function _loop(idx) {
-        valuesList = valuesList.concat([_immutable2.default.List(_this18.columns.map(function (k) {
-          return _this18._data.get(k).iloc(idx);
+        valuesList = valuesList.concat([_immutable2.default.List(_this19.columns.map(function (k) {
+          return _this19._data.get(k).iloc(idx);
         }))]);
       };
 
@@ -1734,14 +1797,14 @@ var DataFrame = function (_NDFrame) {
      */
     ,
     set: function set(columns) {
-      var _this19 = this;
+      var _this20 = this;
 
       if (!Array.isArray(columns) || columns.length !== this.columns.size) throw new Error('Columns must be array of same dimension');
 
       var nextData = {};
       columns.forEach(function (k, idx) {
-        var prevColumn = _this19.columns.get(idx);
-        var prevSeries = _this19.get(prevColumn);
+        var prevColumn = _this20.columns.get(idx);
+        var prevSeries = _this20.get(prevColumn);
 
         nextData[k] = prevSeries.rename(k);
       });
@@ -1786,7 +1849,7 @@ var DataFrame = function (_NDFrame) {
      */
     ,
     set: function set(index) {
-      var _this20 = this;
+      var _this21 = this;
 
       this.set_axis(0, (0, _utils.parseIndex)(index, this._data.get(this.columns.get(0)).values));
 
@@ -1797,7 +1860,7 @@ var DataFrame = function (_NDFrame) {
             v = _ref11[1];
 
         // noinspection Eslint
-        v.index = _this20.index;
+        v.index = _this21.index;
       });
     }
 
@@ -1818,10 +1881,10 @@ var DataFrame = function (_NDFrame) {
   }, {
     key: 'length',
     get: function get() {
-      var _this21 = this;
+      var _this22 = this;
 
       return Math.max.apply(Math, [0].concat((0, _toConsumableArray3.default)(this.columns.map(function (k) {
-        return _this21.get(k).length;
+        return _this22.get(k).length;
       }).toArray())));
     }
   }]);
@@ -2151,4 +2214,54 @@ var mergeDataFrame = exports.mergeDataFrame = function mergeDataFrame(df1, df2,
   }
 };
 
+// Concat
+var _concatDataFrame = exports._concatDataFrame = function _concatDataFrame(objs, kwargs) {
+  if (!(objs instanceof _immutable2.default.List || Array.isArray(objs))) throw new Error('objs must be List or Array');
+
+  if (objs instanceof _immutable2.default.List && objs.filter(function (frame) {
+    return frame instanceof DataFrame;
+  }).size !== objs.size) throw new Error('Objects must all be DataFrame');else if (Array.isArray(objs) && objs.filter(function (frame) {
+    return frame instanceof DataFrame;
+  }).length !== objs.length) throw new Error('Objects must all be DataFrame');
+
+  if (Array.isArray(objs) && objs.length === 1) return objs[0];else if (objs instanceof _immutable2.default.List && objs.size === 1) return objs.get(0);
+
+  var seriesOrderedMap = _immutable2.default.OrderedMap({});
+  if (kwargs.axis === 1) {
+    objs.forEach(function (df) {
+      df.columns.forEach(function (column) {
+        var columnExists = seriesOrderedMap.has(column);
+        seriesOrderedMap = seriesOrderedMap.set(columnExists ? column + '.x' : column, // $FlowIssue
+        columnExists ? df.get(column).rename(column + '.x') : df.get(column));
+      });
+    });
+  } else {
+    objs.forEach(function (df) {
+      var lenSeriesInMap = seriesOrderedMap.keySeq().size === 0 ? 0 : seriesOrderedMap.first().length;
+      var nextLength = df.length + lenSeriesInMap;
+
+      seriesOrderedMap = _immutable2.default.OrderedMap(
+      // Get entries already concated (already in seriesOrderedMap)
+      seriesOrderedMap.entrySeq().map(function (_ref12) {
+        var _ref13 = (0, _slicedToArray3.default)(_ref12, 2),
+            column = _ref13[0],
+            series = _ref13[1];
+
+        if (df.columnExists(column)) return [column, // $FlowIssue
+        (0, _series._concatSeries)([series, df.get(column)], kwargs)];
+        return [column, // $FlowIssue
+        (0, _series._concatSeries)([series, new _series2.default(_immutable2.default.Repeat(NaN, df.length).toList(), { index: df.index })], kwargs)]; // Now merge with columns only in the "right" DataFrame
+      })).merge(_immutable2.default.OrderedMap(df.columns.filter(function (column) {
+        return !seriesOrderedMap.has(column);
+      }).map(function (column) {
+        return (// $FlowIssue
+          [column, lenSeriesInMap === 0 ? df.get(column) : (0, _series._concatSeries)([new _series2.default(_immutable2.default.Repeat(NaN, nextLength)), df.get(column)], kwargs)]
+        );
+      })));
+    });
+  }
+
+  return new DataFrame(seriesOrderedMap);
+};
+
 //# sourceMappingURL=frame.js.map
\ No newline at end of file
diff --git a/src/js/core/index.js b/src/js/core/index.js
index b012fa0..1ddee90 100644
--- a/src/js/core/index.js
+++ b/src/js/core/index.js
@@ -22,6 +22,15 @@ Object.defineProperty(exports, 'DataFrame', {
   }
 });
 
+var _concat = require('./reshape/concat');
+
+Object.defineProperty(exports, 'concat', {
+  enumerable: true,
+  get: function get() {
+    return _interopRequireDefault(_concat).default;
+  }
+});
+
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
 //# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/src/js/core/reshape/concat.js b/src/js/core/reshape/concat.js
new file mode 100644
index 0000000..7003790
--- /dev/null
+++ b/src/js/core/reshape/concat.js
@@ -0,0 +1,55 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+
+var _immutable = require('immutable');
+
+var _immutable2 = _interopRequireDefault(_immutable);
+
+var _frame = require('../frame');
+
+var _frame2 = _interopRequireDefault(_frame);
+
+var _series = require('../series');
+
+var _series2 = _interopRequireDefault(_series);
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+/**
+ * Concatenate pandas objects along a particular axis.
+ *
+ * pandas equivalent: [pandas.concat](https://pandas.pydata.org/pandas-docs/stable/generated/pandas.concat.html)
+ *
+ * @returns {Series | DataFrame}
+ *
+ * @example
+ * const series1 = new Series([1, 2, 3, 4]);
+ * const series2 = new Series([2, 3, 4, 5]);
+ *
+ * // Returns Series([1, 2, 3, 4, 2, 3, 4, 5], {index: [0, 1, 2, 3, 0, 1, 2, 3]})
+ * concat([series1, series2], {ignore_index: false});
+ *
+ * // Returns Series([1, 2, 3, 4, 2, 3, 4, 5], {index: [0, 1, 2, 3, 4, 5, 6, 7]})
+ * concat([series1, series2], {ignore_index: true});
+ */
+var concat = function concat(objs) {
+  var kwargs = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : { ignore_index: false, axis: 0 };
+
+  if (Array.isArray(objs) && objs[0] instanceof _series2.default || objs instanceof _immutable2.default.List && objs.get(0) instanceof _series2.default) return (0, _series._concatSeries)(objs, { ignore_index: kwargs.ignore_index });else if (Array.isArray(objs) && objs[0] instanceof _frame2.default || objs instanceof _immutable2.default.List && objs.get(0) instanceof _frame2.default) return (0, _frame._concatDataFrame)(objs, { ignore_index: kwargs.ignore_index, axis: kwargs.axis });
+  throw new Error('Not supported');
+}; /** 
+    * StratoDem Analytics : concat.js
+    * Principal Author(s) : Michael Clawar
+    * Secondary Author(s) :
+    * Description :
+    *
+    *  (c) 2016- StratoDem Analytics, LLC
+    *  All Rights Reserved
+    */
+
+exports.default = concat;
+
+//# sourceMappingURL=concat.js.map
\ No newline at end of file
diff --git a/src/js/core/series.js b/src/js/core/series.js
index 7e5652e..f76ed31 100644
--- a/src/js/core/series.js
+++ b/src/js/core/series.js
@@ -3,6 +3,11 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
+exports._concatSeries = undefined;
+
+var _toConsumableArray2 = require('babel-runtime/helpers/toConsumableArray');
+
+var _toConsumableArray3 = _interopRequireDefault(_toConsumableArray2);
 
 var _slicedToArray2 = require('babel-runtime/helpers/slicedToArray');
 
@@ -143,6 +148,7 @@ var Series = function (_NDFrame) {
     key: 'map',
     value: function map(func) {
       var array = [];
+      // eslint-disable-next-line
       var _iteratorNormalCompletion = true;
       var _didIteratorError = false;
       var _iteratorError = undefined;
@@ -1449,6 +1455,36 @@ var Series = function (_NDFrame) {
     value: function rename(name) {
       return new Series(this._values, { name: name, index: this.index });
     }
+
+    /**
+     * Append another Series to this and return a new Series
+     *
+     * pandas equivalent: [Series.append](http://pandas.pydata.org/pandas-docs/stable/generated/pandas.Series.append.html)
+     *
+     * @param {Series} other
+     * @param {boolean} ignore_index
+     * @returns {Series}
+     *
+     * @example
+     * const ds1 = new Series([1, 2, 3], {index: [1, 2, 3]});
+     * const ds2 = new Series([2, 3, 4], {index: [3, 4, 5]});
+     *
+     * // Returns Series([1, 2, 3, 2, 3, 4], {index: [1, 2, 3, 3, 4, 5]});
+     * ds1.append(ds2);
+     *
+     * // Returns Series([1, 2, 3, 2, 3, 4], {index: [0, 1, 2, 3, 4, 5]});
+     * ds1.append(ds2, true);
+     */
+
+  }, {
+    key: 'append',
+    value: function append(other) {
+      var ignore_index = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : false;
+
+      // eslint-disable-next-line
+      return _concatSeries( // $FlowIssue
+      [this, other], { ignore_index: ignore_index });
+    }
   }, {
     key: 'kwargs',
     get: function get() {
@@ -1569,4 +1605,35 @@ var Series = function (_NDFrame) {
 
 exports.default = Series;
 
+var _concatSeriesValues = function _concatSeriesValues(objs) {
+  var _Immutable$List;
+
+  return (_Immutable$List = _immutable2.default.List([])).concat.apply(_Immutable$List, (0, _toConsumableArray3.default)(objs.map(function (series) {
+    return series.values;
+  })));
+};
+var _concatSeriesIndices = function _concatSeriesIndices(objs) {
+  var _Immutable$List2;
+
+  return (_Immutable$List2 = _immutable2.default.List([])).concat.apply(_Immutable$List2, (0, _toConsumableArray3.default)(objs.map(function (series) {
+    return series.index;
+  })));
+};
+
+var _concatSeries = exports._concatSeries = function _concatSeries(objs, kwargs) {
+  if (objs instanceof _immutable2.default.List && objs.filter(function (series) {
+    return series instanceof Series;
+  }).size !== objs.size) throw new Error('Objects must all be Series');else if (Array.isArray(objs) && objs.filter(function (series) {
+    return series instanceof Series;
+  }).length !== objs.length) throw new Error('Objects must all be Series');
+
+  if (!kwargs.ignore_index) return new Series(_concatSeriesValues(objs), { index: _concatSeriesIndices(objs) });else if (kwargs.ignore_index) {
+    return new Series(_concatSeriesValues(objs), { index: _immutable2.default.Range(0, objs.reduce(function (a, b) {
+        return a + b.length;
+      }, 0)).toList() });
+  }
+
+  throw new Error('Not supported');
+};
+
 //# sourceMappingURL=series.js.map
\ No newline at end of file
diff --git a/src/js/index.js b/src/js/index.js
index 2fabba2..51ce111 100644
--- a/src/js/index.js
+++ b/src/js/index.js
@@ -18,6 +18,12 @@ Object.defineProperty(exports, 'DataFrame', {
     return _index.DataFrame;
   }
 });
+Object.defineProperty(exports, 'concat', {
+  enumerable: true,
+  get: function get() {
+    return _index.concat;
+  }
+});
 
 var _tools = require('./tseries/tools');