From the first line, this book hooked me: "The day war was declared, a rain of telephones fell clattering to the cobblestones from the skies above Novy Petrograd." A post-Singularity descendant of humanity, the Festival, arrives in orbit around the backwater Rochard's World. The Festival's willingness to share anything in return for information results in economic and social upheaval as the repressed citizens of Rochard's World find they can have anything they want: technology, money, even power. As a result, the New Republic decides to launch a battle fleet to deal with the threat of the Festival.
But their strategy calls for a causality violation gambit, which could be a problem. A capricious and unknowable artificial intelligence, the Eschaton, does not tolerate such time travel ventures, which could imperil its own existence. The Eschaton has been known to retaliate with excessive force—planet-crunching, supernova-type force—and so two human agents hope to intervene before it all goes apocalyptic.
Charles Stross does a wonderful job at contrasting different styles of government and cultures influenced by how they embraced the upheaval of the technological Singularity. The New Republic is modelled after eighteenth-century Russia: technologically and socially conservative, with a strong government enforced by devastating mores and sinister secret police. Then there's Earth, homeworld of our protagonists Martin Springfield and Rachel Mansour. The only entity recognizable as a planetary government would be the United Nations, but as Springfield points out:
It's not the government of Earth; it's just the only remaining relic of Earth's governments that [the New Republic:] can recognize. The bit that does the common-good jobs that everyone needs to subscribe to. World-wide vaccination programs, trade agreements with extrasolar governments, insurer of last resort for major disasters, that srot of thing. The point is, for the most part, the UN doesn't actually do anything; it doesn't have a foreign policy.... Sometimes somebody or another uses the UN as a front when they need to do something credible-looking, but trying to get a consensus vote out of the Security Council is like herding cats.
The conflict of values between the New Republic's agents, specifically its naval officers and an inexperienced secret policeman, and Terrans, specifically Springfield and Mansour, fuels most of the conflict of the book. The rest of the conflict comes from the alien nature of the Festival; the New Republic insists on treating it like an ordinary human government with recognizable motivations and strategy. That turns out to be a costly mistake:
The Festival isn't human, it isn't remotely human. You people are thinking in terms of people with people-type motivations.... You can no more declare war on the Festival than you can declare a war against sleep. It's a self-replicating information network.
Stross also packs the book with the ramifications of technology on cultures: the Festival is an "upload society," where minds are stored in virtual worlds and physical forms are transitory. It's diverged so far from its common ancestry with humans that it's no longer human, as mentioned above, but something else, something that we can't really comprehend. In that way, it's even more alien than the Eschaton, a truly alien entity, but one that at least deigns to communicate with humans on a comprehensible level (once and a while). Unlike too much Singularity fiction, Singularity Sky mixes transhuman, posthuman, and human cultures in a way that makes for interesting but still understandable interaction.
Similarly, while this book is packed to the brim with technobabble and discussions of relativity and quantum mechanics, it never feels too heavy. I love how the characters use entangled qubits for "acausal communication" and the Eschaton one day just decided to relocate 90% o the Earth's population to various planets via wormhole. Maybe that's just because I love theoretical physics more than is healthy; I can see how people less familiar with hard science fiction or physics in general might find the exposition in Singularity Sky daunting. On the other hand, maybe it'll be educational. And to Stross' credit, all of the exposition is relevant to the plot.
As much as I must praise Stross' ideas, I can't in good conscience do the same for the story. The pacing is heavily tilted toward the end (as it should be), but the bulk of its ideas and themes reside in its beginning. As a result, Singularity Sky starts off strong—like I said, it pulled me in—but eventually that siren call of awesomeness asking me not to put down the book petered out. The sense of conflict and suspense just doesn't last, and after the New Republic fleet reaches Rochard's World, the protagonists' plot diverges from that of the fleet, and I never really feel like they're in real danger. With any sense of high stakes obviated, the story withers away into the background.
Singularity Sky starts off strong but ultimately fails to deliver. It has the same great ideas of Alastair Reynolds or Richard K. Morgan but none of their pulse-pounding action and complex mystery subplots that make those books great. People like me, who breathe physics and ponder the possibilities of faster-than-light travel, will find Singularity Sky interesting but come away from the book feeling like it had so much more potential.