diff --git a/src/book/mod.rs b/src/book/mod.rs
index 34e491a9..f1c8e432 100644
--- a/src/book/mod.rs
+++ b/src/book/mod.rs
@@ -47,7 +47,7 @@ pub struct MDBook {
 }
 
 impl MDBook {
-  /// Load a book from its root directory on disk. If a `book.toml` file is present in the
+    /// Load a book from its root directory on disk. If a `book.toml` file is present in the
     /// root directory, the configuration is loaded from that. Otherwise, the
     /// default `Config` is used.
     ///