Fantasy veteran Miéville (Iron Council, 2004, etc.) adds a murder mystery to the mix in his tale of two fiercely independent East European cities coexisting in the same physical location, the denizens of one willfully imperceptible to the other.
The idea’s not new—Jack Vance sketched something similar 60 years ago—but Miéville stretches it until it twangs. Citizens of Beszel are trained from birth to ignore, or “unsee,” the city and inhabitants of Ul Qoma (and vice versa), even when trains from both cities run along the same set of tracks, and houses of different cities stand alongside one another. To step from one city to the other, or even to attempt to perceive the counterpart city, is a criminal act that immediately invokes Breach, the terrifying, implacable, ever-watching forces that patrol the shadowy borders. Summoned to a patch of waste ground where a murdered female has been dumped from a van, Beszel's Detective Inspector Tyador Borlú learns the victim was a resident of Ul Qoma. Clearly, the Oversight Committee must invoke Breach, thus relieving Borlú of all further responsibility. Except that a videotape shows the van arriving legally in Beszel from Ul Qoma via the official border crossing point. Therefore, no breach, so Borlú must venture personally into Ul Qoma to pursue an investigation that grows steadily more difficult and alarming.
Grimy, gritty reality occasionally spills over into unintelligible hypercomplexity, but this spectacularly, intricately paranoid yarn is worth the effort.