diff --git a/README.txt b/README.txt
index 4f439d11dd2ef5d7d855f9763a8389a9ad893ca5..ba03f8ddee2a235f1c18c25a1970df28a4435bfe 100644
--- a/README.txt
+++ b/README.txt
@@ -1,6 +1,9 @@
 KWSys provides a platform-independent API to many common system
 features that are implemented differently on every platform.  This
-library is intended to be shared among many projects.
+library is intended to be shared among many projects, so it has a
+configurable namespace.  Each project should configure KWSys to use a
+namespace unique to itself.  See comments in CMakeLists.txt for
+details.
 
 You are probably reading this file in the source tree of a surrounding
 project.  In that case, see "../README.kwsys" for details of using