Bloomsbury first released Harry Potter and the Philosopher’s Stone in the United Kingdom.
The book was published by Bloomsbury on 26 June 1997. It was Rowling’s first novel and introduced Harry, Ron Weasley, Hermione Granger, and the wizarding school Hogwarts to readers. The book’s initial publication was a major milestone for the relatively small independent publisher.
The title differs between markets. In the United States, Scholastic published the novel under the title Harry Potter and the Sorcerer’s Stone, changing “Philosopher’s” to “Sorcerer’s” for marketing reasons. That difference is why both titles appear in references, although they identify the same first Harry Potter novel.
Bloomsbury continued publishing the main Harry Potter books in the United Kingdom. Scholastic became the series’ principal American publisher, so the publisher depends on which national edition a question means.