What is the name of J.K. Rowling’s fictional book about the sport of Quidditch?

J.K. Rowling’s fictional book about Quidditch is Quidditch Through the Ages.

The book is presented as a history of the wizarding sport, including its development, equipment, rules, and famous teams. In the Harry Potter world, it is part of the Hogwarts library and is credited to the fictional author Kennilworthy Whisp. Rowling wrote the real-world edition as a companion volume to the main series.

The book was published in 2001 alongside Fantastic Beasts and Where to Find Them to raise money for Comic Relief. Its format imitates a library copy, including notes attributed to Harry Potter and his friends, which makes the fictional object feel connected to the novels.

Quidditch Through the Ages is different from The Tales of Beedle the Bard, a collection of wizarding fairy tales, and from Fantastic Beasts, a textbook-style catalog of magical creatures. All three are companion works, but only this title focuses on Quidditch.