4. Solaris
If you're looking for the thinking man's science fiction then you need look no further than Andrei Tarkovsky's 1972 adaptation of Stanislav Lem's Solaris - the genre doesn't get much more cerebral than this. Following on from the news that the small crew of a space station orbiting the fictional planet of Solaris have fallen into an inexplicable emotionally deteriorating state, psychologist Kris Kelvin travels there in order to rectify the situation. Once there, however, he finds himself falling into a state of sorrow, and what unfolds was described by Tarkovsky as a "drama of grief and partial recovery. Tarkovsky was saddened by the lack of intellectual depth in the science fiction genre and this is a meticulous and engrossing counterbalance - Steven Soderbergh demonstrated his cinephilic roots with his own remake of Solaris in 2002 starring George Clooney, which is an impressive and more faithful adaptation of the source material.