diff --git a/README.md b/README.md
index 77551d5..6089ad4 100644
--- a/README.md
+++ b/README.md
@@ -96,7 +96,7 @@ We have a reasonable number of functions implemented, either in our golang core
 
 Building upon those primitives we have a larger standard-library of functions written in Lisp such as:
 
-* `abs`, `apply`, `append`, `cond`, `count`, `filter`, `lower`, `map`, `min`, `max`, `ms`, `nat`, `neg`, `now`, `nth`, `reduce`, `repeat`, `reverse`, `seq`, `strlen`, `upper`, `when`, `while`, etc.
+* `abs`, `apply`, `append`, `cond`, `count`, `false?`, `filter`, `lower`, `map`, `min`, `max`, `ms`, `nat`, `neg`, `now`, `nth`, `reduce`, `repeat`, `reverse`, `seq`, `strlen`, `true?`, `upper`, `when`, `while`, etc.
 
 Although the lists above should be up to date you can check the definitions to see what is currently available:
 
diff --git a/stdlib/stdlib.lisp b/stdlib/stdlib.lisp
index f70415b..f35672c 100644
--- a/stdlib/stdlib.lisp
+++ b/stdlib/stdlib.lisp
@@ -86,6 +86,11 @@
 (define even? (lambda (n) (zero? (% n 2))))
 (define odd?  (lambda (n) (! (even? n))))
 
+;;
+;; is the given argument "true", or "false"?
+;;
+(def! true?  (fn* (arg) (if (eq #t arg) true false)))
+(def! false? (fn* (arg) (if (eq #f arg) true false)))
 
 ;; Square root
 (define sqrt (lambda (x:number) (# x 0.5)))