Perhaps the best science fiction move made after 2001. Deliberately slow, so as to confuse the Soviet censor, the affected pace increases the claustrophobic feeling induced by watching the 4 main protagonists in fear for their minds.
And why are they so afraid? Because the planet Solaris, which they orbit, holds a giant living ocean, one that appears to be able to create any person found in their subconsciousnesses. For the main character, this means a re-introduction to his dead wife - a woman who commited suicide because of him.
The ending of this movie gets me everytime. Even thinking about it makes the spine quiver with delight.