The Cat in the Hat script, with Chris Meledandri as producer, and Audrey Geisel as the executive producer. However, the project never came to fruition. On January 24, 2018, it was announced that Warner Animation Group was in development of a different animated "Cat in the Hat" film as part of a creative partnership with Seuss Enterprises. In 2009, the Royal National Theatre created a stage version of the book, adapted and directed by Katie Mitchell. "Seussical", a musical adaptation that incorporates aspects of many Dr. Seuss works, features the Cat in the Hat as narrator. The musical received weak reviews when it opened, in
The Cat in the Hat for the series, including "The Cat in the Hat Comes Back" (1958), "Green Eggs and Ham" (1960), "Hop on Pop" (1963), and "Fox in Socks" (1965). He initially used word lists of limited vocabularies to create these books, as he had with "The Cat in the Hat", but moved away from the lists as he came to believe "that a child could learn any amount of words if fed them slowly and if the books were amply illustrated". Other authors also contributed notable books to the series, including "A Fly Went By" (1958), "Sam and the Firefly" (1958), "Go, Dog.