Each of the five books follows the main character, Harry Potter, and his friends at Hogwarts School of Wizardry.
The books have sold more than 100 million copies and been translated into 47 languages.
They're so popular that a first edition of the first book would now be worth around £15,000.
The fifth book, Harry Potter and the Order of the Phoenix, came out in June 2003 and sold 1 million copies in the UK on its first day - the fastest-selling book in history.
What are the books about?
