diff --git a/Doc/lib/libmutex.tex b/Doc/lib/libmutex.tex
index 54369449a98..d6e3707b537 100644
--- a/Doc/lib/libmutex.tex
+++ b/Doc/lib/libmutex.tex
@@ -8,7 +8,7 @@
 
 The \module{mutex} defines a class that allows mutual-exclusion
 via aquiring and releasing locks. It does not require (or imply)
-and threading or multi-tasking, though it could be useful for
+threading or multi-tasking, though it could be useful for
 those purposes.
 
 The \module{mutex} module defines the following class: