When Kris Kelvin arrives at the planet Solaris to study the ocean that covers its surface, he finds a painful, hitherto unconscious memory embodied in the living physical likeness of a long-dead lover. Others examining the planet, Kelvin learns, are plagued with their own repressed and newly corporeal memories. The Solaris ocean may be a massive brain that creates these incarnate memories, though its purpose in doing so is unknown, forcing the scientists to shift the focus of their quest and wonder if they can truly understand the universe without first understanding what lies within their hearts.
Mind blowing classic!
FYI, there was a new English translation that came out 2011. However, it looks like it's only available as an ebook.
Solaris by Stanisław Lem
A psychologist arrives at a research space station called Prometheus, his mission to ascertain whether research into the mysterious planet of Solaris should be terminated. He finds Prometheus all but deserted, its straggling crew seemingly haunted by hallucinations of figures from their pasts.