Charlie Stross's longrunning Merchant Princes series are a sneaky, brilliant techno-economic thought experiment disguised as heroic fantasy, and with Empire Games, the first book of the second phase of the series, Stross throws in a heavy dose of the noirest spycraft, an experiment in dieselpunk Leninism and War on Terror paranoia.

Empire Games is a fresh start in the series, quickly establishing the backstory that spans the previous seven volumes: a clan of worldwalking transdimensional mercantalists have quietly taken over their medieval, parallel world by establishing a triangle trade in ours: they bring messages from their world's kingdoms into our dimension and use telephones and computers to get them across the planet in a hot second; then they take heroin from our world and transport it by mule train across their world, creating an unstoppable — and unbelievably profitable — courier service that catapults them to power.

When the clan is fractured by factionalism and discovered by the US Department of Homeland Security, the catastrophic war drives the remainder of the clan into Timeline 3, a dieselpunk version of North Korea where an exiled English tyrant rules over all of the Americas, brooding at the French imperial usurpers who hold all of Europe. With the clan's help, the King is overthrown and a kind of worker's paradise is established in Timeline 3, with the top priority task of leapfrogging American technological prowess before the DHS shows up and nukes them all into oblivion.

That's where Empire Games starts: the US has become a surveillance state that exceeds even our own paranoid moment, where privacy is shredded by adversarial genomics, internet-of-surveilling-things, and a paranoid deep state pierced through with conspiracy theorists, Dominionists, even highly placed Scientologists.

What's more, they've just figured out that the clan's worldwalkers are still dropping by to pick up technological resources to export to World 3, where the revolutionaries are on an accelerated course of technological development, like the post-Sputnik space race, but for every imaginable technology.

Lucky for the DHS, they've figured out how to make non-worldwalking clan members into worldwalkers by tweaking their biochemistry, and even luckier, they've got a few candidates to work as double-agents for them and set up a forward base in whatever timeline their adversaries are using as their new home. Chief among these is Rita, the adopted-out daughter of Miriam, the hero of books 1-t, who was raised by paranoid refugees from East Germany who have taught her a suspiciously large amount of spycraft on the way.

What follows is a brilliant spy novel, intricately plotted and beautifully told — but posed against a backdrop of economic speculation that uses science fiction to play out some of the longrunning arguments that kicked off with Leninism and its insistence that peasants could use capitalist technology to leapfrog the industrial revolution and go straight to socialist abundance, with dashes of Deng's "Communism with Chinese characteristics" and the post-Soviet doctrine of "emerging markets" that would use technology and markets to supercharge their economy.

Contrasting that with the brooding, moribund, paranoid USA in the grips of a terminal War on Terror, Stross plays with Mutually Assured Destruction, palace intrigue, technocratic triumphalism and the paranoid style of American politics to wonderful effect, ending on a cliffhanger that will have you baying for the next volume, which, happily, was published last month, and is next on my list.

If you missed books 1-7 of this wonderful series and were daunted by the prospect of having to read them to get up to speed, this is a great place to start fresh (but seriously, read those ones too).

Empire Games [Charles Stross/Tor Books]

Dark State [Charles Stross/Tor Books]