Writers dealing with that knottiest of problems in fiction – to what extent can they describe cultures and societies not their own without appropriation, an insulting level of ignorance and/or launching a social media storm – are going about it in different ways. The latest novel by Sebastian Faulks is set in the future (where, pleasingly, everyone still needs a coat, phew). Val McDermid has gone the other way and returned to smoky, bottom-pinching years, starting with 1979.

Francis Spufford’s solution to writing about race – and race in America at that – is to propose an alternate reality, invent an intensely detailed city to do it in, and extrapolate new words from the remnants of an ancient language known as Mobilian trade jargon. It’s certainly an original approach. So, in his new book, black people are taklousa, white people are takata and Native Americans are takouma.

How this will work for you in practice depends very much on how you read. If you are an every-word reveller, you will have no problem, and indeed will love this lush, luxuriant book. But if you are a vertical speed king, you may find yourself cursing, constantly turning back to the explanatory note, and eventually making up a mnemonic about what means what, which is conceivably worse than remembering the words Spufford uses in the first place. (I would strongly recommend this sort of reader to get hold of a physical copy rather than reading on download.)

How the approach works on the larger canvas of sensitivity – where people can spit ‘You filthy takouma’ with impunity – is an interesting question, as we follow Spufford’s mixed-race detective through a racially motivated crime. In the fictional city of Cahokia (near the real St Louis), the smallpox virus that wiped out much of the native population in America did not evolve into its most serious variant, leaving the takouma more in charge of their own affairs than elsewhere. When a takata –  a Ku Klux Klan member, indeed – is found ritualistically murdered, it threatens the stability of the city. Joe Barrow, an orphan and jazz pianist manqué, is the mostly straight cop in this hardboiled, swell dames, Prohibition, gangster world.

The plot does not move speedily. Cahokia Jazz lacks the near-unbearabletension of Spufford’s Golden Hill and the lovely storytelling wistfulness of his Light Perpetual. But he is one of the best writers we have at turning a book into a magical doorway to somewhere else. Take a trip to Cahokia’s Union Station in 1922, with its statues in alcoves of ‘Prince Cuauhtemoc the Fifth and Last shaking hands with Ulysses S. Grant’, where ‘behind them on the track to their right an immense locomotive passed, 60 feet of black steel gouting steam, and, gliding after it, grey-and-gold car after grey-and-gold car, the eastbound Usunhiyi’ – the ‘Evening Land’ train, that goes to California, to sunset, the way the dead go, according to takouma legend. 

At first I couldn’t figure out what this book reminded me of. There is something of Michael Chabon’s The Yiddish Policemen’s Union and a little of Colson Whitehead. But eventually I realised what it was: the surreal, alternative American city of Maurice Sendak’s In the Night Kitchen. Utterly immersive, vivid, off-kilter and unnerving. As a straight detective story, it is flawed; as a novel about race, it is a little confusing; but as a full-bore sensory experience, it glows through the fog.