The Hogwarts library contains tens of thousands of books on thousands of shelves. Included in its many sections is an Invisibility Section, a section with information about dragons, and a Restricted Section at the back, set off with a rope. A signed note from a teacher is required to peruse that section of the library; it contains books of Dark Magic only used by older students studying advanced Defence Against the Dark Arts. One of the books in this section screams when opened.
