A man walks into a bar and gets castrated by someone wielding a Stanley knife. A woman drinking in a fashionable bar has her cocktail laced with sleeping pills by a serial rapist. Gunshots ring out across the suburbs and the gardai seem powerless to stop them.

The new Ireland is a dangerous place. You can get stabbed for a random glance or less, mugged in broad daylight or conned out of your savings by a charmer with a plausible telephone manner. In the new Dublin, it’s as easy to get murdered walking down Grafton Street at night as in a northside tower block, and everybody knows it. Prosperity begets fear.

In the rational part of our minds, we try to deal with the fear in a sensible way, by fitting extra locks and taking care about where we walk. But fear has a power that reaches deep into the mind, far below the level where reason makes a difference. Down there we turn to ritual and magic: we make what psychologists call apotropaic signs, gestures to fend off evil.

Irish noir, a new blend of American-style hard-boiled crime fiction and the tropes of 21st-century Ireland, is undergoing a boom. It has become our favoured act of magic, a ritual to ward off the darkness. But the most interesting aspect of Irish noir is its very existence: why, of all the lenses in all the looking-glasses in the world, should we choose this one to scrutinise ourselves with? Storytelling is one of the oldest and most potent of our apotropaic rituals. We sublimate our fears by exposing them; we hope that by exposing them to daylight we can banish them, or at least weaken their hold over us.

We tell horror and ghost stories to exorcise the demons that haunt us. And we tell crime stories — truly horrible, ugly, violent tales of greed and revenge — in the subconscious hope that we will never be visited by such monsters.

Crime fiction, like its cinematic sibling film noir, used to be a distinctively American genre. A few Irish writers, such as the Dublin novelist John Connolly, still work on this assumption: he sets his bestselling thrillers in the American state of Maine and avoids conscious Irish references.

But a new generation of crime writers has seen the vital connection between the genre and boom-time Ireland. Novelists such as Ken Bruen, Gene Kerrigan, Cormac Miller and Ingrid Black (a pseudonym for the journalist Eilis O’Hanlon) have reinvigorated the genre with an Irish setting, thus creating a template for Irish noir.

So potent is the connection that it has now been internationalised. Bruen is the editor of Dublin Noir: The Celtic Tiger vs The Ugly American, featuring stories set in Ireland by an eclectic mix of American and native writers.

What these writers share is a sense that 21st-century Ireland is the ideal noir locale. The potent mix of prosperity and fear creates an environment where the genre flourishes. At their best, they can go even further; not just latching onto Dublin as a backdrop, but using the noir form to probe the contradictions of affluence.

Superficially, noir transplants so easily because there are precise similarities between America in the 1920s — when the style first surfaced in the writings of Raymond Chandler and Dashiell Hammett — and contemporary Ireland. For the Celtic tiger, read the Roaring Twenties and the economic boom that preceded the Wall Street crash. For mobsters such as Dillinger and Capone, read criminal gang bosses like John Gilligan. For prohibition-era speakeasies, read hedonistic nightclubs and drug dens.

If you look closely enough, the link was apparent for a long time. Orson Welles’s 1948 film The Lady from Shanghai, famous for its climactic shoot-out in a hall of mirrors, was originally called Black Irish, and this was a couple of years before French critics began to describe such movies as “noir”.

America in the 1930s had its share of Irish mobsters. Some were immortalised in films such as Machine Gun Kelly and The Rise and Fall of Legs Diamond; others had to wait for 1990s irony, such as the Coen brothers’ pastiche gangster movie Miller’s Crossing.

Oddly, however, the new wave of Irish noir fiction has not developed a home-grown cinematic equivalent. Where film is concerned, noir has become a look, a way of stylising the characters and the set. Fintan Connolly’s movies Flick and Trouble with Sex depict a thoroughly noir-looking Dublin full of moody shadows and drenched in blue light, but there is no corresponding heart of darkness in the plot.