Which Harry Potter novel was the first to sell more than 10 million copies in its first 24 hours?

Harry Potter and the Deathly Hallows was the first Harry Potter novel to sell more than 10 million copies in its first 24 hours.

The seventh and final novel was released on 21 July 2007. In the United States, Scholastic reported first-day sales of more than 8 million copies, while worldwide first-day sales were reported at more than 11 million copies. The launch became one of the largest events in publishing history.

The novel concludes Harry’s conflict with Lord Voldemort and follows Harry, Ron, and Hermione as they search for objects connected to Voldemort’s immortality. Unlike earlier books, much of the story takes place away from Hogwarts.

The title refers to three legendary magical objects: the Elder Wand, the Resurrection Stone, and the Cloak of Invisibility. These objects form a central part of the book’s mythology and explain its title.