Stanislaw Lem's book Solaris blew me away when I first read it. I remember thinking that the author could not have been of this world. He managed something so few other sci-fi writers manage; to write about another world as though he had been there to witness and experience it. It gives you a strange feeling when you read it; you understand in some uncanny way that the author had first-hand knowledge of this other planet. But how could he have? The story gets under your skin and doesn't leave you. I recommend the book, and also the 2002 film Solaris, directed by Steven Soderbergh, and starring George Clooney and Natascha McElhone. Like the book, the film also got under my skin. I've read the book twice and seen the film several times.