diff --git a/viewer/index.html b/viewer/index.html
index 792e67e..17cab63 100644
--- a/viewer/index.html
+++ b/viewer/index.html
@@ -1,6 +1,8 @@
 <!DOCTYPE html>
 <html>
-<head>
+<head><script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-1322994160563832"
+     crossorigin="anonymous">
+  </script>
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <title>EPUB.js + Hypothesis Example</title>
@@ -42,4 +44,4 @@ <h2 id="author">...</h2>
   </div>
 
 </body>
-</html>
\ No newline at end of file
+</html>
