Imaginary Worlds: the Art of Fantasy is a study of the modern literary fantasy genre written by Lin Carter. It was first published in paperback by Ballantine Books in June, 1973 as the fifty-eighth volume of its celebrated Ballantine Adult Fantasy series; it was the only nonfiction entry in the series. The book was among the earliest full-length critical works devoted to fantasy writers and the history of fantasy. It was the third of three such studies by Carter, being preceded by Tolkien: A Look Behind "The Lord of the Rings" (1969) and Lovecraft: A Look Behind the "Cthulhu Mythos" (1972). These works, together with his editorial guidance of the Ballantine Adult Fantasy series, established Carter as an authority on the genre.