Blue Mars by Kim Stanley Robinson: Well, I think the last book didn't quite live up to the promise of the first two. Which isn't really saying much. The series as a whole is remarkable. It's the kind of series you read once and then think about for the next ten years in fits and starts, with it sometimes influencing your thoughts on particular subjects. This book had a lot about aging in it, a lot about how the mind adapts to changes. It also had some amazing thoughts on how people who appear to be complete polar opposites might be far closer than they ever realized. This is not an easy series to read, and I found myself getting more and more annoyed at the deliberate pace of the final book as I got closer to the end. I was also disturbed, slightly, by the sheer lack of ending... until I realized that was part of the point. The books covered three revolutions on Mars, and not much beyond that. If you want to read this series, I recommend trying to read it section by section as quickly as possible, and don't slow down at the end or you'll end up disturbed by the finish as I was.