Kennilworthy Whisp is the fictional author credited with writing Quidditch Through the Ages in J.K. Rowling’s wizarding world.
Quidditch Through the Ages is presented as a reference book about the history and rules of the wizarding sport. Rowling wrote it as a companion volume to the Harry Potter books, using the fictional author’s name to make the book appear to come from inside the magical world.
The real-world edition was published in 2001 by Bloomsbury under Rowling’s name, with proceeds supporting Comic Relief. Its library-style format describes the development of broom games, the equipment used in Quidditch, famous teams, and changes to the sport’s rules.
Kennilworthy Whisp should not be confused with other fictional wizarding authors. Newt Scamander is credited with Fantastic Beasts and Where to Find Them, while Bathilda Bagshot wrote A History of Magic. Those names belong to different in-universe books and characters.