What is the name of J.K. Rowling's first published book for children?

J.K. Rowling's first published book for children was Harry Potter and the Philosopher's Stone.

Bloomsbury published the novel in the United Kingdom on 26 June 1997. It introduces eleven-year-old Harry Potter, who discovers that he is a wizard and begins studying at Hogwarts. The book establishes major characters including Hermione Granger, Ron Weasley, Albus Dumbledore, and Lord Voldemort.

The novel's American edition is titled Harry Potter and the Sorcerer's Stone, which can make the answer appear different across sources. “Philosopher's Stone” is the original British title and the title used in most countries outside the United States. Rowling's first published children’s book is also her first published novel overall; later companion books, such as Fantastic Beasts and Where to Find Them, are supplementary works rather than the beginning of her fiction career.