Like the Medicis, Miriam's family sometimes overreaches its influence, and in the previous installment of the series, The Clan Corporate, their machinations caused a power-hungry young prince to blow up the royal palace before Miriam could be forced to marry his brother. Fleeing the carnage, she washes up in the third alternate Earth, New London, a parallel New York that's in the early throes of the Industrial Revolution and ruled by a capricious English king. Women have no rights in this world, and with her family, U.S. government agents and the secret Polis of New London hunting her, Miriam's resources are dwindling.

The situation in the other two dimensions is just as dire: Prince Egon, also known as the Pervert, is moving to consolidate his usurpation of the throne, while here in the 21st century, the few United States agents who are aware of the worldwalkers are engaged in a frantic search for a nuclear bomb. Planted by a vengeful member of Miriam's family, this weapon is hidden somewhere in Boston ... and it is set to go off in just a few months!

Worldbuilding that's crystal clear

Twenty-first-century politics and high-fantasy intrigue make remarkably good bedfellows in Stross' The Merchant Princes series: the author roams from the modern-day War on Terror to the ethics of new reproductive technologies, along the way slipping in snapshots of government oppression as conducted by kings, warlords and allegedly democratic societies. Miriam, as a modern woman forced to cope with everything from federal agents to a society that won't let her buy a newspaper (unless a man does it for her), makes an excellent lens for viewing the civilizations that preceded our own, not to mention present-day America itself. The world-building in this series is simply superb, in other words—it is engaging, crystal-clear and disturbingly real.

In maintaining three universes (all of them embroiled in crisis) and pushing along a number of promising subplots, Stross rarely keeps readers in one place for long. The narrative jumps from Miriam's point of view to that of her hunters, then to her would-be boyfriend, a hapless DEA agent named Mike, before checking in on the campaigns of Prince Egon and the revolutionary schemers of New London. Readers who prefer to sink into one storyline at a time may find this jarring; it gives the flow of The Merchants' War an abrupt, staccato feel. Still, the various storylines do tie together in logical, yet surprising, ways.

None of that necessarily favors audiences who are jumping into the story late, or who may not yet have committed to continuing to read on. It might be easy enough to catch up on Miriam's past, but Stross' story stops short just when things are becoming truly exciting. By its end, all of the major players in all three worlds have run around a good deal, but none has achieved any significant character growth. Naturally, these are criticisms that have been leveled against this series—and many others before it—in the past. For those who don't mind hanging in for the long haul, The Merchants' War is fast-paced and engrossing and will leave readers ravenous for the next installment.