diff --git a/src/transforms/select.d.ts b/src/transforms/select.d.ts
index 74fe57a4fa..642921431f 100644
--- a/src/transforms/select.d.ts
+++ b/src/transforms/select.d.ts
@@ -7,22 +7,77 @@ export type SelectorFunction = (index: number[], values: any[] | null) => number
 
 export type SelectorChannel<T> = {[key in keyof T]?: SelectorName | SelectorFunction};
 
+/** How to select points within each series. */
 export type Selector<T> = SelectorName | SelectorFunction | SelectorChannel<T>;
 
+/** Options for the select transform. */
 export interface SelectOptions {
   z?: ChannelValue;
 }
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, then selects points from each
+ * series based on the given selector. The selector can be specified as:
+ *
+ * - *first* - the first point by input order
+ * - *last* - the last point by input order
+ * - a {*channel*: *min*} object - the minimum point by the given *channel*’s value
+ * - a {*channel*: *max*} object - the maximum point by the given *channel*’s value
+ * - a {*channel*: function} object to filter based on series index and channel values
+ * - a function to filter based on series index
+ *
+ * For example to select the maximum point of the *y* channel, like selectMaxY:
+ *
+ * ```js
+ * Plot.text(data, Plot.select({y: "max"}, options))
+ * ```
+ *
+ * When the selector is specified as a function, it is passed the index of each
+ * series as input, along with channel values if a *channel* name was given; it
+ * must return the corresponding index of selected points (a subset of the
+ * passed-in index).
+ */
 export function select<T>(selector: Selector<T>, options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the first
+ * point from each series in input order.
+ */
 export function selectFirst<T>(options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the last
+ * point from each series in input order.
+ */
 export function selectLast<T>(options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the minimum
+ * point from each series based on *x* channel value.
+ */
 export function selectMinX<T>(options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the minimum
+ * point from each series based on *y* channel value.
+ */
 export function selectMinY<T>(options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the maximum
+ * point from each series based on *x* channel value.
+ */
 export function selectMaxX<T>(options?: T & SelectOptions): Transformed<T>;
 
+/**
+ * Groups points into series according to the *z* channel, or the *fill* or
+ * *stroke* channel if no *z* channel is provided, and then selects the maximum
+ * point from each series based on *y* channel value.
+ */
 export function selectMaxY<T>(options?: T & SelectOptions): Transformed<T>;