The Monster Book of Monsters is a book about magical creatures.
It is the required textbook for Care of Magical Creatures class in Harry Potter’s third year (PA1, PA4). Hagrid sends Harry a copy for his birthday, but he has to hold it shut with a belt as the book scuttles around like a crab and snaps at Harry as though it had jaws.
During the first Care of Magical Creatures lesson, Hagrid was disappointed to find out that none of the students had discovered the secret to opening their books safely – stroking the spine (PA6).
From the Web
Harry Potter Wiki: The Monster Book of Monsters