I bought this book purely for the Bujold story, but the rest are okay, too. The premiss is "love conquers all, in an SFnal setting". Some are a bit gloopy (Bujold obviously is not one of these -- and the story is excellent) and some are more fantasy than SF, but there are some interesting backgrounds and characters here.
Sauscony Valdoria -- Soz -- is a bio-enhanced Jagernaut pilot fighting in the war between her Skolian Empire and the Aristo Traders. But she is much more than that, and she finds herself fighting for her Empire, her love, her honour, and her sanity. The story is obviously set up for a sequel (The Radiant Seas), but still manages a satisfying closure.
Primary Inversion is a great fusion of hard SF ideas with an in-depth character story. There is a lot of juicy new technology, all with a realistic flavour of being based on solid extrapolation of physics. We get a new kind of FTL 'inversion' drive, hand weapons that use matter-antimatter annihilation, nanotechnology sidewalks, a quantum mechanical explanation of telepathy, biomechanical augmentation for pilots, and hacking into galactic computer networks. We also get galaxy-spanning human empires that are thousands of years old, despite the story being set just a few hundred years in the future, due to a fun little plot device. And this all provides a richly textured background for Sauscony's story, as she comes to terms with her various war traumas, and with her destiny. A beautifully told human story, with great background technology. I was hooked.
Seventeen-year-old Mayan Tina meets a strange man lost on the streets of LA -- Althor talks of spacecraft and other mad things, yet she is strangely drawn to him. But he isn't mad, and after some adventures she ends up in his world, the Skolian Empire (set some time after the events of Primary Inversion -- the war is over, but the hostilities aren't). And her troubles are just beginning: the Traders want both Althor and her for their telepathic abilities; there are hidden enemies on their own side; and there are heavy political ramifications of her relationship with Althor. It seems all they can trust is Althor's Jag spaceship, and a planetful of 6000-year-old bodyguards.
I like all the hard science details here -- lots of quantum mechanics and relativity, alternate universes as Riemann sheets, and a great AI spaceship -- and we also learn a bit more of the confusing historical background of the Skolian and Trader Empires. I particularly liked Tina's synaesthetic empathy: Joshua's surprise made yellow loops in the air. (But all this good stuff is rather too submerged by the foreground love story for my taste.)
Kelricson Valdoria, yet another half-sibling of the Skolian Imperator, crashes on Coba, a Restricted world. The matriarchs of Coba have faked their Restricted status to turn away the interest of the Empire, so they cannot afford to let Kelric go home. Instead he ends up being passed from Estate to Estate in a spiralling intrigue that may end in disaster for all.
I'm afraid I found two of the major plot premisses unbelievable. That every single one of the matriarchs should become infatuated with Kelric in turn seems ... too convenient. And the Quis dice game seems too powerful: I can just about believe that it might capture the structure of differential equations, and hence be used to express scientific concepts -- but I don't see how it could also be used to design political strategy.
Nevertheless, the action keeps going throughout. The plot device of moving Kelric around the Estates lets us see the different cultures on Coba, and watching the Cobans rediscover technology is fun. And the ever-growing tragedy, as Kelric acts as a catalyst for devastating change, when all he wants to do is go home, is well handled.
This is a direct sequel to Primary Inversion, carrying on the story of Sauscony Valdoria and Jaibriol Qox II, each the heir to interstellar empires that are deadly enemies, as they go into hiding to be together. Their disappearances make relations between their respective empires worse. When finally the Aristos discover Jaibriol is still alive, they abduct him, and force him to become a puppet ruler. But this is their mistake, as Soz returns to wage all out war to get him back.
This is fun stuff, with gobs of weird physics, sarcastic interchanges with imbedded computers, the sacrifices people make to become leaders, vast interstellar battles, and a little bit of love story to drive the plot. Some of the info-dumping could be done a little more smoothly, but on the whole this is a rip-roaring adventure in a large, complex, interesting universe.