Harry Potter fan fiction based on Harry Potter
The Harry Potter fandom is the community of fans of the Harry Potter books and films who participate in entertainment activities that revolve around the series, such as reading and writing fan fiction, creating and soliciting fan art, engaging in role-playing games, socialising on Harry Potter-based forums, and more. The fandom interacts online as well as offline through activities such as fan conventions, participating in cosplay, tours of iconic landmarks relevant to the books and production of the films, and parties held for the midnight release of each book and film.
By the fourth Harry Potter book, the legions of fans had grown so large that considerable security measures were taken to ensure that no book was purchased before the official release date. Harry Potter is considered one of the few four-quadrant, multi-generation spanning franchises that exist today, despite Rowling's original marketing of the books to tweens and teens.