A book I've read recently that I would recommend was Timeline by Michael Crichton. I have read several of his books and enjoyed them. I just love the research he puts into them. This one was about Time Travel (a favorite thing of mine). Much better than the movie of course. But now I want to watch the movie again so I can say "HA" when they make stupid deviations.
The characters are really well developed, the story moves along at a good pace, and at the end I even went back to reread a couple of bits. The technology is always convincing enough to make me want to research more myself. He had a very interesting take on time paradox and alternate realities that I'm not sure makes sense. I love to argue time paradox.. so everyone needs to read this book so we can talk specifics.