In which Harry Potter book does J.K. Rowling introduce the Triwizard Tournament?

J.K. Rowling introduces the Triwizard Tournament in Harry Potter and the Goblet of Fire.

The fourth Harry Potter novel was published in 2000. It describes a dangerous international competition involving champions from Hogwarts, Beauxbatons Academy of Magic, and Durmstrang Institute. The champions face three tasks involving a dragon, the Black Lake, and a maze.

The Goblet of Fire selects one champion for each participating school, but Harry’s name emerges as a fourth entry. Because contestants must normally be of age, his unexpected selection becomes a major source of tension. Cedric Diggory represents Hogwarts alongside Harry, while Fleur Delacour and Viktor Krum represent the visiting schools.

The tournament provides the structure for much of the novel and leads directly to the return of Lord Voldemort. The book was adapted as the fourth film in the main Harry Potter movie series, released in 2005.