I was crossing borders when I read The City & the City, taking the journey home to my parents’ house in north-west France by plane and train from where I live in Berlin. It was the first time I had done that journey; my first Christmas after moving to the once famously divided German capital. A friend had sent me a copy of China Miéville’s book and there was something about the shadowy cover that made it look like the perfect companion for a trek through the cold and snow.

At the time, I knew nothing about Miéville nor his work. But if I looked up at all from it on that trip home, it was to utter an dumb-struck ‘Huh!’ at the frozen landscape, before swiftly diving back into the story of Inspector Tyador Borlú’s murder investigation in a city—or cities—like no other.

Down-at-heel city-state Besźel is an anomaly somewhere in central Europe—but the strength of Miéville’s story is just how brilliantly he convinces readers (or convinced me at least) of his stunning premise: that Besźel competes for the same physical space as another city, Ul Qoma. Ul Qoma is a more prosperous sibling, a place of glimmering skyscrapers, incense and sugar-fried peas. But Ul Qoma and its inhabitants are not to be seen by their Besź counterparts and vice-versa. The rival cities co-exist in denial, hide in plain sight, in certain neighbourhoods where they spill into each other’s space, creating problematic, disputed exclaves. Passers-by must carefully “unsee” traffic, buildings, inhabitants from the opposite city—and even “unsmell” those frying delicacies.

It’s a brilliant idea, the concept of the border extrapolated to reveal its absurdity—but in lesser hands than Miéville’s, it’s one that could remain too conceptual or be too clumsily rendered to totally hook readers. Thankfully, we’re in the hands of a master storyteller—and I was amazed at how I bought into Besźel with a giddy page-turning delight that only the best fiction provides. It helps, that from the get-go, Miéville roots us firmly in a familiar genre before sliding in a sense of what’s really going on. The book starts with the discovery of a woman’s dead body, the arrival on the scene of the police, the gruff narration of a jaded detective—we’re straight into a police procedural. While genre can sometimes get bogged down in clichés, it serves its function perfectly here, giving the reader a set of conventions he or she can lean on as things get weird. Instead of getting hung up on doubts, we’re speeding ahead, eager to find out whodunit.

It’s the vocabulary that Miéville invents for his world that really allows him to pull off his sleight of geography though. Maps of Besźel are divided into areas of “total”, “alter” and “crosshatch”—the different degrees of presence in the local space—rendered with enough technical twang to sound convincingly like the product of a bureaucracy designed to keep the two cities apart. But what I like most about these word choices, is how used they feel—it’s like Miéville searched out a first degree of vocabulary for his world, then pushed it further, imagined how through daily use it might have become more grammatically bent out of shape. We know what “alter” means as a verb for example. We’re less used to seeing it as a noun. Instead of an adjective, “total” also becomes a noun. Not total something—just total. These words have been given a patina that reflects the way we really use language. They sound like second-hand words coming from the mouths of Besźel’s inhabitants, not gleaming new coinage from an earnest author. They feel all the more established and convincing because of it. The same can be said for Miéville’s term “breach”—used here without an article, as an abstract noun—the act of slipping between the two cities, a heinous crime: “Is there any chance we’re looking at breach?” asks a probing Borlú for example. This is language with an oral edge that plants us in a living, breathing world.

Add to that the culture Miéville invents around his world’s defining feature and it’s impossible not to fall for its impossibilities. Academics study “the cleavage” that wrought Besźel and Ul Qoma, uppity “Unifs” campaign to unite the two cities, and an authoritarian state tries to keep them and ordinary Besz on a tight leash to prevent just that. That’s where the unseeing comes in—neatly described here, as inspector Borlú strides through an area of crosshatch: “I watched the local buildings’ numbers. They rose in stutters, interspersed with foreign alter spaces. In Besźel the area was pretty unpopulated, but not elsewhere across the border, and I had to unseeing dodge many smart young businessmen and –women. Their voices muted to me, random noise.”

If you’re a reader in a busy city, you might find that passage all too easy to believe. How often are we guilty of unseeing as we charge through the streets—without the excuse of the powerful security apparatus that enforces the practice in Besźel? The truth is, we all have our priorities and prejudices and there are times in our hectic lives, we find ourselves averting our eyes from things we would rather not see. Perhaps it’s here that we find something closest to the truth in Miéville’s story—the precursor in our own lives to the stringent divisions in The City and the City. We should be mindful of the borders that we conjure around us—even more absurd than lines drawn on maps—lest we blind ourselves to the danger of forces seeking to split the crosshatch of our lives into total and alter.

Titus Chalk is a writer in Berlin and the author of Generation Decks: The Unofficial History of Gaming Phenomenon Magic: The Gathering. He is a fugitive from the British class system, surviving mostly on jazz and chocolate éclairs. You can find him on twitter @tituschalk