This is book 5 the the Merchant Princess series. Start at the beginning with The Clan Corporate if you mean to read these; it's very much one ongoing story in multiple volumes. And this volume ends with a doozy of a cliffhanger.
This volume is definitely a continuation of the series: readers who've enjoyed the ride so far should continue to enjoy it; those who weren't won't find much new and different to bring them in. Bigger and more complicated issues are taking hold. Stross does take more explicit aim at how the US government operates with respect to terrorism and national security issues, and the nasty stuff seems all too likely to be true to life. Times are becoming very interesting in multiple worlds, but it's also starting to show some signs that the world may be getting beyond the author's control. Although it was exciting at the time, I finished it weeks ago, and I find that I don't remember the details of the plot too well. This partly reflects that there's a whole lot going on, and partly that my memory is terrible, but I think it also reflects that it's not that good.
7 out of 10.
**** PLOT HIGHLIGHTS -- SPOILERS ****
These are the bits that I remember. Sorted by threads of action, not in the order they're presented.
The US government has learned about the nukes that the Clan stole, and they're really mad. So when they recover the one that Matthias gave back to them when he defected, they want to use it. Since their captive scientists have manage to make something, apparently using cultured brain cells from captured clan agents, that can cross the world barrier, they have the ability. So they drop their nuke across into a the castle in Niejwein where the Clan's forces were being besieged by the Pervert. Unfortunately for the US spooks, the Clan guys had just bugged out to New Britain, and the nuke actually goes off on the Pervert's forces, decapitating their army. Despite the fact that the attack actually hit their enemies, the Clan doesn't like being nuked, and they still have a few, which they sneak into Washington, with the timer going to zero as the book ends, leaving us unsure if it worked or not.
Meanwhile, the less crazy people in the Clan are busy doing research into the interworld travel phenomenon, and seem to be pretty close to figuring out how to go to many different places, not just the known couple.
Meanwhile, the geopolitical situation in New Britain has fallen apart; the king has abdicated and the revolution that Miriam's contacts were trying to foment actually seems to be taking hold, but of course it's just in its infancy.
Miriam is getting herself installed as the Queen in Niejwein, because it's the best way to make sure people who won't kill her fill the power vacuum, but she's far from comfortable with the situation.