What was J.K. Rowling’s first published Harry Potter book?

J.K. Rowling’s first published Harry Potter book was Harry Potter and the Philosopher’s Stone.

The novel was published in the United Kingdom by Bloomsbury on 26 June 1997. It introduces Harry Potter, Hogwarts School of Witchcraft and Wizardry, Ron Weasley, Hermione Granger, and the series’ central conflict with Lord Voldemort.

In the United States, Scholastic published the same book under the title Harry Potter and the Sorcerer’s Stone. The American title is not a different story or a later volume; it reflects a change made because the publisher believed “sorcerer” would be more immediately understandable to American readers. The British title refers to the alchemical philosopher’s stone.