With last year's Empire Games, Stross restarted the series, taking it to a new phase that doesn't require the reader to be familiar with the first seven volumes (though they are fantastic reads and thoroughly recommended in their own right).
Like the first seven books, the Empire Games books are works of tremendously fun and thought-provoking political/economic speculation, in which a small clan of people with the hereditary means to traverse the barriers between parallel universes ("worldwalking") create a variety of trade arrangements across timelines with different levels of technological sophistication and paranoid surveillance states.
But Empire Games takes it to a new level; the first series was something like a police procedural or crime novel, about the potential for worldwalking drug cartels. This new series is about a new cold war, in which the nuclear tipped-arsenals of a paranoid, maddened version of the USA are seeking a lock through the multiverse for the worldwalkers, who have taken up residence in an alternate dieselpunk Earth that they are desperately attempting to bring through an accelerated information revolution so they can attain nuclear deterrence before the US finds them.
Stross's police-state America is darkly hilarious, incredibly capable and also quite mad, a rogues' gallery of Dominionists and Scientologists whose religious doctrines are the only thing standing between the awesome might of the state and total dominance over its citizenry. Meanwhile, his revolutionary parallel timeline, gripped by a succession crisis and internal rivalries, is a beautifully realized parallel society whose dizzying rate of change is something like post-Deng China, but driven by a WWII-style military-industrial pulling-together for mutual defense against an all-powerful foe.
Meanwhile, the actual spy novel that animates all this poleconomic speculation is first-rate: sporting a rogue cell of abandoned deep-cover Stasi families, worldwalking missions to spirit high-level defectors across multiple timelines, and a ticking-bomb McGuffin in the form of a parallel universe in which a vastly technologically advanced civilization seems to have deliberately turned the Earth into a tame black hole the size of a walnut…
Like Empire Games, Stross ends this book on a precipitious cliff hanger, with a note to expect another volume next January.
Dark State: A Novel of the Merchant Princes Multiverse [Charles Stross/Tor]