The library contains tens of thousands of books on thousands of shelves. The different sections include an Invisibility Section, a section on dragons, and the Restricted Section at the very back, barred by a rope. Students need a signed note of permission from a teacher to peruse the Restricted Section, as it holds books about powerful Dark subject matter that is never taught at Hogwarts, and is only used by older students studying advanced Defence Against the Dark Arts. Books in the Hogwarts library may be put on hold and the student's name added to a waiting list. Chocolate and presumably, all other food and drinks are forbidden in the library, which closes at 8:00 p.m. Irma Pince is the librarian. She guards the books fiercely, and has been known to put unusual jinxes on the books, to make sure that they are not mistreated