Someone mentioned Stanislaw Lem in the Sunday Papers comments, and I got thinking that I would really recommend his Memoirs Found in a Bathtub to anyone who likes Portal 2. Not so much the story, but I felt they have a similar kind of atmosphere.
Are there are books that you think would be enjoyable to people who like a particular game?
(And the first person to mention the Strugatsky brothers or Andrzej Sapkowski's books will win a prize. I call it the Trophy of Stating the Bleeding Obvious.)