I read this awhile ago, though it was the last thing I read: Speaker for the Dead by Orson Scott Card. It's the follow up to Ender's Game, though the novels are completely different. I think I may have preferred this one, and though perhaps the Piggies - the slang term for the new alien species they encounter - aren't terribly convincing, Card's ability to write humans is excellent. I may now have to read the third one.