Harry Potter is a book series.
Bloomsbury Publishing plc ( formerly M.B.N. 1 Limited and Bloomsbury Publishing Company Limited ) is a British independent , worldwide publishing house of fiction and non-fiction . Harry Potter is a series of fantasy novels written by British author J. K. Rowling . Since the release of the first novel , Harry Potter and the Philosopher 's Stone , on 26 June 1997 , the books have found immense popularity , critical acclaim and commercial success worldwide . , the books have sold more than 500 million copies worldwide , making them the best-selling book series in history , and have been translated into seventy-three languages . The original seven books were adapted into an eight-part film series by Warner Bros. .