diff --git a/README.md b/README.md
index 456787f..c5cbbdd 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@
 
 ## Installation
 
-[promise.hpp][promise] is a single header library. All you need to do is copy the header file into your project and include this file:
+[promise.hpp][promise] is a header only library. All you need to do is copy the header files (invoke.hpp and promise.hpp) into your project and include this file:
 
 ```cpp
 #include "promise.hpp"