“Harry Potter fandom” refers to the community of fans of the Harry Potter books and movies 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, socializing on Harry Potter-based forums, and more. The fandom interacts online as well as offline through activities such as fan conventions, 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. Harry Potter fans usually call themselves “Potterheads”, though some may refer to themselves as “witches/wizards” or “Pottermaniacs”. By the fourth Harry Potter book, the legions of Harry Potter fans had grown so large that considerable security measures were taken to ensure that no book was purchased before the official release date. Studies on the fandom have shown that both children and adults are fans, despite Rowling’s original marketing of the books towards children aged nine to twelve.