diff --git a/content/book/_index.md b/content/book/_index.md
index 10253e2..0c17487 100644
--- a/content/book/_index.md
+++ b/content/book/_index.md
@@ -1,4 +1,5 @@
 ---
+type: single
 ---
 
 <img src="/book/cover-front.png" style="margin: 0 auto; display: block; width: 500px; max-width: 100%;" />