diff --git a/lib/utils/fs.js b/lib/utils/fs.js
index <HASH>..<HASH> 100644
--- a/lib/utils/fs.js
+++ b/lib/utils/fs.js
@@ -28,6 +28,7 @@ var getFiles = function(path) {
         'node_modules',
 
         // Skip book outputs
+        '_book',
         '*.pdf',
         '*.epub',
         '*.mobi',
Add _book to list of files to ignore