This plugin is pretty funny. Basically, what this does is that when you right click on a shelf, it opens a "menu-inventory", with many books. You can configure these books to execute commands when you click them.
/bookshelf - open bookshelf inventory.
/bookshelf reload - reload plugin
You can add more books and change their actions if you edit the config.yml
Issues : https://bitbucket.org/rockcodes/rockbookshelf/issues