The Lost Worlds of 2001 is a 1972 novel by Arthur C. Clarke that followed the first novel in the Space Odyssey series. While the novel is not the sequel to 2001: A Space Odyssey, The Lost Worlds of 2001 is still an accompaniment to it. The book consists of behind-the-scenes notes from Clarke about scriptwriting and production issues. Also included in the book is Clarke's short story, The Sentinel, on which Stanley Kubrick's film adaptation of 2001: A Space Odyssey is loosely based.