diff --git a/Doc/source/index.rst b/Doc/source/index.rst
index c513504ae..5397a34f0 100644
--- a/Doc/source/index.rst
+++ b/Doc/source/index.rst
@@ -287,6 +287,7 @@ Table of Contents
 
 .. toctree::
    :maxdepth: 2
+   :caption: Library
 
    afmLib
    agl