Merlin's book

Merlin's book was a book so named because it was believed to have formerly belonged to Merlin. At some point, it came into the possession of one of the Headmasters of Hogwarts School of Witchcraft and Wizardry, and was kept in the Headmaster's study. The subject of the book is unknown, but it is known to have been written in an unfamiliar runic alphabet.

Appearances

 * Pottermore