Harry Potter is a series of seven fantasy novels written by British author J. K. Rowling. The books chronicle the adventures of the adolescent wizard Harry Potter and his best friends Ron Weasley and Hermione Granger, all of whom are students at Hogwarts School of Witchcraft and Wizardry.
The central story arc concerns Harry's struggle against the evil wizard Lord Voldemort, who killed Harry's parents in his quest to conquer the wizarding world and subjugate non-magical people (Muggles).
Several successful derivative films, video games and other themed merchandise have been based upon the series.

Since the 1997 release of the first novel Harry Potter and the Philosopher's Stone, which was retitled Harry Potter and the Sorcerer's Stone in the United States, the books have gained immense popularity, critical acclaim and commercial success worldwide.
As of June 2008, the book series has sold more than 400 million copies and has been translated into 67 languages,[2][3] and the last four books have consecutively set records as the fastest-selling books in history.

English-language versions of the books are published by Bloomsbury in the United Kingdom, Scholastic Press in the United States, Allen & Unwin in Australia, and Raincoast Books in Canada.
Thus far, the first six books have been made into a series of motion pictures by Warner Bros., with the sixth, Harry Potter and the Half-Blood Prince, released on 15 July 2009.
The series also originated much tie-in merchandise, making the Harry Potter brand worth £15 billion. The seventh book will be made into two movies released six months apart.