Again, I had plenty of 'Y' titles, but Jim Young's The Face of the Deep is such a wonderful example of classic science fiction that I couldn't pass up the chance to mention it. If you love great science fiction, give this one a try! You won't regret it.
I found this book at a yard sale and thought it sounded promising. I'm so glad I did. It's a very fast read and incredibly good. He also wrote another book called Armed Memory that I really want to get my hands on.