The Unincorporated War (TUW) is the sequel to Dani Kollin and Eytan Kollin's The Unincorporated Man (TUM). While you could probably read and enjoy TUW without reading TUM, the first is the better of the two books, and there is really no reason to read them out of order.
TUW is a direct continuation of TUM, and it shares that same basic feel and story. While I enjoyed it, I felt that it was overall not as good as the first book. In part this was because there is comparatively little new development of future technology and related wonders; we saw most of the exciting new future stuff in the first book. TUW is also more poorly edited than the first book, with occasionally clumsy wording, clumsy foreshadowing, and passages that could be shortened or dropped without losing anything.
Overall, I don't think that I recommend TUW unless you really like the first book. It's okay, but there are much better things to read. While it is interesting to hear about what happens with all the characters, there's a lots of chaff to go through to get to the nuggets of goodness spread throughout. There are some good bits; the military strategy is well-done and engaging, and TUW does have the same general feel of the first book. Unfortunately, TUW is open-ended, leaving nothing resolved. Whether or not it is worth reading will depend in large part on what happens in the third book (which I do not currently have access to). Given the decidedly lackluster showing put forth in this book, I may not take the time to hunt the final book down.
Spoilers For The First Book Ahead!
Justin Cord and Neela (now Neela Cord) have moved to Ceres, where Justin finds that he is at the center of a massive disincorporation movement. He's basically okay with this, but is rather taken-aback at how fast things are moving -- and more so when it becomes apparent that the human race is perfectly willing to break a 300-year-long peace over the issue.
The Solar System quickly divides itself into the Inner Planets and the Outer Alliance, and a long and drawn-out war begins. Justin's old nemesis, Hecktor Sambianco, is back and he quickly takes over the Inner Core's war efforts. It's not long before permanent deaths become commonplace, and both economies are devoted to churning out warships at an ever-increasing rate.
The avatars take a much larger role in this book, although they are just plain silly in their limitations, lack of inventiveness, and need to mimic human imagery in the neuro. I felt that their story was a major drawback to the book; they are over-dramatic, unpredictable, and poorly written.
There's not much more I can say without giving away spoilers, but it is worth noting that this book becomes even more of a soap opera than the first. Hecktor is more evil, Justin more morally inflexible, and the war gives a perfect vehicle for drama, grandiose gestures, and suffering -- and more of this is strongly foreshadowed for the future. Despite the fact that this is a highly political war, the authors do not spend as much time on political theory as they did in the last book, instead focusing on war and the newly rediscovered religious movements in the asteroids and outer planets. These are not bad things, but they are more familiar and less inventive than the social and political themes of the first book.
The Unincorporated War is followed by The Unincorporated Woman.