As noted before me, this book isn't one you can just grab and read alone. Unlike the early Cobra books, this one drops you right into the thick of new events that were outlined at the previous book's ending. Without having read that you would be hopelessly lost.
Timothy Zahn is a master of building the story until an explosion of revelations. This one is a departure from that. It builds and builds and builds, and does so wonderfully. It doesn't 'end' like his usual books because unlike them this is a first of a series that appears to be a single story rather than closely connected independent stories. I find that to be an interesting development, and certainly has me craving for more. If I wasn't fan I might have been annoyed by it (as it feels like he is forcing people to come back), but then again you are going to be a fan if you end up reading this one, as you are bound to have read at least some of the preceding Cobra books (and likely many more Zahn novels). There are surprises and intricacies in usual Zahn style, everyone seems to have plots within plots, and every time you think you know what will happen, something else happens.
The only thing that doesn't sit entirely well with me, and hence the 4 stars, is the fact the Dominion of Man's motivations are very much left unmentioned (what use are a few weak and underpopulated planets to a huge sprawling empire). I'm sure it is plotdevice, but this is a big thing that I don't feel should be left unanswered until book 2 (and knowing him I wouldn't even be surprised if he waits until book 3 now that he has left it open for the entirety of book 1). It makes the Dominion look even pettier than it apparently is.
Also, why are the Cobra worlds taking all the crap lying down? They were left for 100 years to fend for themselves, underequipped, underpopulated and with little capacity for pretty much anything, now the Dominion comes along as if nothing happened and demands obedience and loyalty? I really hope that this is expanded upon.
I guess I had two things I didn't like. But his history marks him as a master of the long the development, so I'm assuming it is just a little longer than usual. And it would fit with the lack of the usual 'ending' in a series book.
So if you are a fan of Zahn and have read the other Cobra books, this one is downright required reading.