diff --git a/lisp/custom.el b/lisp/custom.el
index d9d0898dcb7..bc155d32dd0 100644
--- a/lisp/custom.el
+++ b/lisp/custom.el
@@ -237,6 +237,8 @@ The following keywords are meaningful:
 
 :type	VALUE should be a widget type for editing the symbol's value.
 	Every `defcustom' should specify a value for this keyword.
+        See `(elisp) Customization Types' for a list of base types
+        and useful composite types.
 :options VALUE should be a list of valid members of the widget type.
 :initialize
 	VALUE should be a function used to initialize the