Robots and Empire is the greatest book ever written by Isaac Asimov, and the best book I have ever read to date (7-18-99), SF or not. It discusses things I often think about in my philosophical moments, such as how limited our thoughts are by how our brain is designed. It's an amazing book, and you should read it. Read the other books in the Robot series before you read it, or it won't make any sense at all.