diff --git a/index.rmd b/index.rmd
index bad9503..dd78a38 100644
--- a/index.rmd
+++ b/index.rmd
@@ -12,7 +12,7 @@ To be published by O'Reilly in July 2016.
 
 <img src="cover.png" width="250" height="328" alt="Cover image" />
 
-## Table of contents
+## Table of contents {#toc}
 
 <ul class="toc">
   {% include package-nav.html %}