Since the release of the first novel Harry Potter and thePhilosopher's Stone on 30 June 1997, the books have gained immense popularity, critical acclaim and commercial success worldwide. The series has also had some share of criticism, includingconcern for the increasingly dark tone. As of June 2011, the book series has sold about 450 million copies, making it the best-selling books series in history and has beentranslated into 67languages, and the last four books consecutively set records as the fastest-selling books in history.
A series of many genres, including fantasy and coming of age (with elementsofmystery, thriller, adventure, and romance), it has many cultural meanings and references. According to Rowling, the main theme is death, although it is primarily considered to be a work ofchildren's literature. There are also many other themes in the series, such as prejudice and corruption.
The initial major publishers of the books were Bloomsbury in the United KingdomandScholastic Press in the United States. The books have since been published by many publishers worldwide. The books, with the seventh book split into two parts, have been made into an eight-part filmseries by Warner Bros. Pictures, the highest-grossing film series of all time. The series also originated much tie-in merchandise, making the Harry Potter brand worth in excess of $15 billion.