Which J.K. Rowling novel was adapted into two films, the only Harry Potter story split this way?

Harry Potter and the Deathly Hallows was the J.K. Rowling novel adapted into two films. Harry Potter and the Deathly Hallows – Part 1 was released in 2010, followed by Part 2 in 2011.

The book is the seventh and final novel in the Harry Potter series. It follows Harry, Ron, and Hermione as they leave Hogwarts and search for Voldemort’s remaining Horcruxes, objects that contain parts of his soul.

The split allowed the filmmakers to preserve more plot and character material from the longest concluding book. Part 1 focuses heavily on the trio’s mission and the growing danger around them, while Part 2 presents the return to Hogwarts and the final battle.

The six earlier novels were each adapted as one feature film. The two-part conclusion therefore produced eight movies from seven books, rather than seven movies from seven books.