Nanofuture : What's Next For Nanotechnology

This book is really great for these reasons:
1. It explains why and how machines made w/ molecules as their constituent parts are possible.
2. It shows how the progression of nanotechnology will occur if we can make it happen, and speculates on the amazing ramifications of this.
3. Its historical overview of engines and explanations of concepts like entropy and information theory are the best and most understandable I've ever read.

This is a book whose author is not afraid to think big but grounds it all within a historical perspective.