I am a member of a book club ("Read it and Eat!"), and our most recent book was Cryptonomicon by Neal Stephenson. I was one of those who recommended it, as I had read it before (at least twice) and enjoyed it so much it has made my list of "favorites" (see left-hand column). I must say I enjoyed it just as much this time!
The book is part thriller and part historical novel. The narrative switches each chapter between current time (circa 1995) and WWII. There are 2 main families we follow, the Shaftoes and the Waterhouses, and their lives are interwoven, both in the past and in the modern-day sections. Stephenson does a great job of switching back and forth between the families, and between times, and we see how the modern generation of each family is a product of their ancestors. Some may find the transition between stories a bit jarring or hard to follow at first, but once the characters become more fleshed out, it's really quite fun to see how Stephenson ties it all together.
But, the book is really about codes and code-breaking, with a little bit of computer hacking. It's an exciting story incorporating Nazis, geeks (both modern day and historical), gold and high-finance in a fast-paced (for the most part) book. Even the "dry" historical sections where we see the birth of computing are told through the eyes of those involved, so one can feel the excitement of discovery.
While the book is long (~900 pages) it is very readable and the characters are all quite interesting. If there is a nit to pick, it's the propensity of Stepehnson to ramble on (in some detail) about minor incidents and characters. Most of these sections do nothing to move the plot forward, but, in their defense, they do add color and ambience to the story. However, I think the book would be just as enjoyable (and not turn away so many readers) if the editor had been a bit more ruthless with the scissors.
The characters are for the most part fairly well-developed, especially as related to the story. We are privy to their thoughts and attitudes, all of which are unique and interesting - for example, Bobby Shaftoe, the Haiku-composing, heroin-addicted Marine.
One of the things I enjoy most about the book (besides the cool code-breaking/computer stuff!) is Stephenson's wry sense of humor that he injects in many characters/scenes. The reaction of one character during the raid on Pearl Harbor is a great example of this, as is a section where this same character meets the woman who will become his wife. These sections are found throughout the book, and help to make the story lines even more enjoyable.
The biggest disappointment was the ending - first, because I didn't want the story to end, and secondly because it all ends rather abruptly. It seems as if the author realized he had to end the book, and so wrapped things up as quickly as possible. I was left feeling a little cheated. But, not enough to make me dislike the book! The rest of the book is as good a read as I've had in years, and its inventiveness and characters make up for any shortcomings.