What an awesome book. There is so much to say about it, I'm not even going to try for anything but a broad overview. Neal Stephenson has done an amazing job, creating a world with 4000 years of history. Even though the story is a little heavy on the science, math, and philosophy, you don't need to understand everything it throws at you to enjoy it. The story draws you in and keeps an excellent narrative, even though it encompasses a lot of rich, well developed characters and several settings that are completely different. When a book ends, I'm usually ready; I'm generally not the type to wish there was more, especially with a book this long. Not only did I want it to continue, I'm considering re-reading it, which I basically never do (too many other good books waiting to be read). Having said all that, I wouldn't recommend it to everyone. It took me about 100 pages to get with the flow of the story. There is so much vocabulary and history. I generally don't have patience for this type of book, having tried and failed to read Dune and LOTR. That being said, if you like sci-fi/fantasy books, and you want to read one great one for a while, This is it.