What was the first Harry Potter book J.K. Rowling completed?

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

Rowling developed the idea for Harry Potter during the early 1990s and worked on the manuscript before it was accepted for publication by Bloomsbury. The completed novel established the characters, magical rules, school setting, and long-term conflict that supported the rest of the series.

The book’s publication in 1997 made Rowling a published author, but completion came before the later novels were written. The title can cause confusion because American readers know the same work as Harry Potter and the Sorcerer’s Stone. It remains the first novel in the seven-book sequence, regardless of which English title appears on the cover.