The HBO prequel It: Welcome to Derry has the perfect opportunity to confirm a popular Stephen King fan theory. With close to 70 books and 200 short stories, the horror author is by far one of the most prolific writers of the past century. Good onscreen versions of his stories aren’t scarce, but Andy Muschietti’s duology, It and It: Chapter Two, is one of the best Stephen King movie adaptations. As such, the announcement of a prequel called It: Welcome to Derry received overwhelming excitement from fans.