Solaris (novel)

A novel by Stanislaw Lem, published in Warsaw in 1961. It was adapted into to a film in the late 1970s and 2002 (see Solaris (movie)).

Warning: Wikipedia contains spoilers

The novel is about a scientific investigation on a planet with a strange ocean, which turns out to be, possibily, alive. Lem uses this as a device to dig deeply into human psychology.

see also science fiction, Andrei Tarkovsky