Which J.K. Rowling novel was published in 2005 as the sixth Harry Potter book?

Harry Potter and the Half-Blood Prince was J.K. Rowling’s sixth Harry Potter novel, published in 2005.

Bloomsbury released the book in the United Kingdom on 16 July 2005. The novel continues Harry’s sixth year at Hogwarts and combines school life with a deepening investigation into Lord Voldemort’s past. Albus Dumbledore gives Harry private lessons based on memories that reveal important information about Voldemort’s development and ambitions.

The title refers to a mysterious annotation in Harry’s Potions textbook. The notes help Harry excel in class, but the identity of the Half-Blood Prince becomes an important revelation later in the story. The term is not the name of a new student or a Hogwarts house.

The book was followed by Harry Potter and the Deathly Hallows in 2007. Its film adaptation was released in 2009, directed by David Yates, with Daniel Radcliffe, Rupert Grint, and Emma Watson returning in the principal roles.