The book: The world's best-selling sci-fi novel has won just about every award in the genre.
Why it's unfilmable: The density. The book takes on politics, religion, technology, ecology, relationships and giant sand worms.
The movie: "Several of the characters in Dune are psychic, which puts them in the unique position of being able to understand what goes on in the movie." -- Janet Maslin, New York Times
"Most sci-fi movies offer escape, a holiday from homework, but Dune is as difficult as a final exam. You have to cram for it." -- Richard Corliss, TIME Magazine