Harry Potter was a very popular fantasy novel series. It told the story of an orphan, Harry Potter, who discovered that he was a wizard on his eleventh birthday and was taken to Hogwarts School of Witchcraft and Wizardry to study magic. The Harry Potter series had a large number of fans around the world and created many derivative works including movies, music, games, etc. It's a very subjective question about which one is the best because everyone has different opinions and preferences about the Harry Potter series. Some of you may have preferred the first Harry Potter and the Sorcerer's Stone, some of you may have preferred the second Harry Potter and the Chamber of Secrets, some of you may have preferred the third Harry Potter and the Prisoner of Azkaban, some of you may have preferred the fourth Harry Potter and the Goblet of Fire. Overall, the Harry Potter series was a very classic novel series, and both the book and the movie were worth watching.