Which Harry Potter book did J.K. Rowling complete first?

J.K. Rowling completed Harry Potter and the Philosopher’s Stone first.

It is the opening novel of the seven-book Harry Potter series and introduces the central conflict between Harry Potter and Lord Voldemort. Harry discovers that he is a wizard shortly before beginning his first year at Hogwarts, where he meets Ron Weasley and Hermione Granger.

Rowling conceived the idea for Harry during a delayed train journey from Manchester to London in 1990. She developed the characters and planned the broad series structure before the first book was published. The manuscript eventually attracted the attention of literary agent Christopher Little and was acquired by Bloomsbury.

The book appeared in Britain in 1997 and won major children’s-literature awards. Its American edition used the title Harry Potter and the Sorcerer’s Stone, but “Philosopher’s Stone” is the original British title and the title used in the first publication. Later books continued the story rather than serving as alternate versions of this beginning.