germ. boka „[Runen]zeichen, Buchstabe” >dt. Buch >engl. booklet ; engl. book ;
The arrow ">" does not always mean an etymological derivation.
Sometimes it may be just a conjecture (even a refuted one), or an error.
Take the tree as a suggestion for lookup, e.g. try http://etymonline.com/index.php?search=booklet