You've read the book, now see the movie. The cast is stellar: Richard Burton takes it to the limit as the poet MacPhisto, Marlon Brando seems to be training for Apocalypse Now, James Coburn gets to ham it up as a brain butcher, Ringo Starr has his first role away from his bandmates. I hadn't realised John Huston acted as well as directed. Ewa Aulin plays the ingenue. Christian Marquand is in charge but clearly not in control: the result of all this talent was an unwatchable mess with very little to recommend it. Which is exactly what I expected, so I wasn't disappointed.
Roger Ebert: three stars. Renata Adler in contradiction.