diff --git a/Doc/Manual/Contents.html b/Doc/Manual/Contents.html
index e52a02aba..2fc23c354 100644
--- a/Doc/Manual/Contents.html
+++ b/Doc/Manual/Contents.html
@@ -1,4 +1,5 @@
 
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <HTML>
 <HEAD>
 <TITLE>SWIG Users Manual</TITLE>
diff --git a/Doc/Manual/maketoc.py b/Doc/Manual/maketoc.py
index efdea03ed..c78bcfd13 100644
--- a/Doc/Manual/maketoc.py
+++ b/Doc/Manual/maketoc.py
@@ -6,6 +6,7 @@ chs = open("chapters").readlines()
 
 f = open("Contents.html","w")
 print >>f, """
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 <HTML>
 <HEAD>
 <TITLE>SWIG Users Manual</TITLE>
