Lem strongly seconded. I just listed him in my own comment because no one had mentioned him yet, and alas, three minutes later you bring him up.
Thirded. I recommend "The Chain of Chance" to LW readers - not SF, but a detective novel with a fascinating take on probability, rationality and reasoning.
Aside: "The Chain of Chance" is an awful title... the original title was "Hay Fever" ("Katar" in Polish). "The Chain of Chance" is a spoiler for an idea that creeps up like a mouse and hits like Mike Tyson.
Aside #2: I was a big fan of Lem from my teens, read his books, and met him in person. Lem lived near my uncle's house in Krakow. I visited my uncle i...
I have never read very much Science Fiction, unlike some of the people here on Less Wrong, and I think I would like to. At least, the few books I have read I enjoyed. I've read a couple of books from Asimov's Foundation Series, two Michael Crichton books, Twenty Thousand Leagues Under the Sea by Jules Verne, and an anthology of SciFi short stories (no really famous authors) that my dad owned.
That list looks very short. I just finished reading a fiction book, and am looking to start another. Recommendations? What are the two or three books I simply must read?