diff --git a/Documentation/Books/Makefile b/Documentation/Books/Makefile
index 1f75410e0e..5e6fa9f36a 100644
--- a/Documentation/Books/Makefile
+++ b/Documentation/Books/Makefile
@@ -5,16 +5,16 @@ all: build-books
 MDPP_FILES = $(wildcard *.mdpp */*.mdpp */*/*.mdpp)
 
 md-files:
-  @for file in $(basename $(MDPP_FILES)); do echo "converting $${file}.mdpp"; markdown-pp.py $${file}.mdpp $${file}.md; done
+	@for file in $(basename $(MDPP_FILES)); do echo "converting $${file}.mdpp"; markdown-pp.py $${file}.mdpp $${file}.md; done
 
 
 .PHONY: build-books
 
 build-books: md-files
-  @test -d books || mkdir books
-  make build-book NAME=Users
+	@test -d books || mkdir books
+	make build-book NAME=Users
 
 build-book:
-  @test -d books/$(NAME) || mkdir books/$(NAME)
-  cd $(NAME) && gitbook build -o ../books/$(NAME)
-  cp Users/arangodb_logo2.png books/Users/
\ No newline at end of file
+	@test -d books/$(NAME) || mkdir books/$(NAME)
+	cd $(NAME) && gitbook build -o ../books/$(NAME)
+	cp Users/arangodb_logo2.png books/Users/