Which Harry Potter book did J.K. Rowling complete as the series finale?

J.K. Rowling completed the Harry Potter series with Harry Potter and the Deathly Hallows. Bloomsbury published the seventh and final novel in the United Kingdom on 21 July 2007.

The novel follows Harry, Ron, and Hermione as they leave Hogwarts to find and destroy the remaining Horcruxes. It also develops the legend of the three Deathly Hallows: the Elder Wand, the Resurrection Stone, and the Cloak of Invisibility. The title combines these magical objects with the story’s themes of mortality, sacrifice, and power.

The book became a major publishing event. More than eight million copies were sold in the United States during its first 24 hours, according to Scholastic. The story was later adapted into two films, released in 2010 and 2011.

The final novel is sometimes confused with Harry Potter and the Half-Blood Prince, which is book six and sets up the final conflict. Deathly Hallows is the concluding volume, although Rowling later expanded the fictional universe through companion works and the stage play Harry Potter and the Cursed Child.