Which J.K. Rowling book introduced the fictional sport Quidditch?

Harry Potter and the Philosopher’s Stone introduced the fictional sport Quidditch.

The first Harry Potter novel presents Quidditch as the wizarding world’s broomstick sport. Harry learns the rules at Hogwarts, joins the Gryffindor team as a Seeker, and plays in school matches. The sport uses four balls: one Quaffle, two Bludgers, and a Golden Snitch.

The Snitch is worth 150 points and usually ends a match when caught, although the team with the most points wins. This unusual scoring system is a frequent source of confusion because catching the Snitch does not automatically guarantee victory.

Rowling later published Quidditch Through the Ages, a companion book credited to the fictional author Kennilworthy Whisp. That book expands the sport’s invented history, but the sport itself first appears in Philosopher’s Stone.