Chrestomanci, sometimes branded The Worlds of Chrestomanci, is a heptalogy of children's fantasy books written by British author Diana Wynne Jones, published from 1977 to 2006. In the context of the parallel universe setting of the books, Chrestomanci refers to both the British government office that is responsible for supervising the use of magic and Chrestomanci Castle in southern England, which is both residence and headquarters. Jones gives the pronunciation "KREST–OH–MAN–SEE" herself and one of her characters writes the same instruction for using the word as a spell. Source: Wikipedia (en)