diff --git a/README.md b/README.md
index 0c2bd07..0ef1f90 100644
--- a/README.md
+++ b/README.md
@@ -95,6 +95,9 @@ This template defines some new variables to control the appearance of the title
 - `footer-right` (defaults to the page number)
 	
 	the text on the right side of the footer
+- `book` (defaults to `false`)
+
+    typeset as book.
 
 ## Examples