diff --git a/lispref/numbers.texi b/lispref/numbers.texi
index b8361d52820..e233a9f1d9f 100644
--- a/lispref/numbers.texi
+++ b/lispref/numbers.texi
@@ -135,6 +135,16 @@ arguments to such functions may be either numbers or markers, we often
 give these arguments the name @var{number-or-marker}.  When the argument
 value is a marker, its position value is used and its buffer is ignored.
 
+@defvar most-positive-fixnum
+The value of this variable is the largest integer that Emacs Lisp
+can handle.
+@end defvar
+
+@defvar most-negative-fixnum
+The value of this variable is the smallest integer that Emacs Lisp can
+handle.  It is negative.
+@end defvar
+
 @node Float Basics
 @section Floating Point Basics