diff --git a/ChangeLog b/ChangeLog
index fbf251771..9b1938ae6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2008-05-27  Matthias Clasen  <mclasen@redhat.com>
 
+	* README.in: Add a note about G_DISABLE_SINGLE_HEADERS.
+
 	* NEWS: Updates
 
 2008-05-27  Matthias Clasen  <mclasen@redhat.com>
diff --git a/README.in b/README.in
index b5527f45b..a0d618dfe 100644
--- a/README.in
+++ b/README.in
@@ -24,6 +24,16 @@ Installation
 
 See the file 'INSTALL'
 
+Notes about GLib 2.18
+=====================
+
+* The recommended way of using GLib has always been to only include the
+  toplevel headers glib.h, glib-object.h and gio.h. GLib enforces this by 
+  generating an error when individual headers are directly included. 
+  To help with the transition, the enforcement is not turned on by 
+  default for GLib headers (it is turned on for GObject and GIO).
+  To turn it on, define the preprocessor symbol G_DISABLE_SINGLE_INCLUDES.
+  
 Notes about GLib 2.16
 =====================
 
@@ -31,7 +41,6 @@ Notes about GLib 2.16
   and libselinux for extended attribute and SELinux support. Use 
   --disable-xattr and --disable-selinux to build without these.
 
-
 Notes about GLib 2.10
 =====================