THE neat streets of Oslo are not a natural setting for crime fiction. Nor, with its cows and country smells, is the flat farming land of Sweden's southern tip. And Reykjavik, Iceland's capital, is now associated more with financial misjudgment than gruesome murder. Yet in the past decade Nordic crime writers have unleashed a wave of detective fiction that is right up there with the work of Dashiell Hammett, Patricia Highsmith, Elmore Leonard and the other crime greats. Nordic crime today is a publishing phenomenon. Stieg Larsson's Millennium trilogy alone has sold 27m copies, its publishers' latest figures show, in over 40 countries. The release this month in Britain and America of “The Girl with the Dragon Tattoo”, the film of the first Larsson book, will only boost sales.

The transfer to the screen of his sprawling epic (the author died suddenly in 2004 just as the trilogy was being edited and translated) will cement the Nordics' renown. The more unruly subplots have been eliminated, leaving the hero, a middle-aged financial journalist named Mikael Blomkvist (Michael Nyqvist), and an emotionally damaged computer hacker, Lisbeth Salander (Noomi Rapace, pictured above), at the centre of every scene. The small screen too has had a recent visit from the Swedish police. Starting in 2008, British television viewers have been treated to expensive adaptations of the books of Henning Mankell, featuring Kenneth Branagh as Kurt Wallander. The BBC series has reawakened interest in Mr Mankell's nine Wallander books, which make up a large slice of his worldwide sales of 30m in 40 languages.

Larsson and Mr Mankell are the best-known Nordic crime writers outside the region. But several others are also beginning to gain recognition abroad, including K.O. Dahl and Karin Fossum from Norway and Ake Edwardson and Hakan Nesser of Sweden. Iceland, a Nordic country that is not strictly part of Scandinavia, boasts an award winner too. Arnaldur Indridason's “Silence of the Grave” won the British Crime Writers' Association Gold Dagger award in 2005. “The Devil's Star” by a Norwegian, Jo Nesbo, is published in America this month at the same time as a more recent novel, “The Snowman”, is coming out in Britain. A previous work, “Nemesis”, was nominated for the prestigious Edgar Allan Poe crime-writing award, a prize generally dominated by American authors.

Three factors underpin the success of Nordic crime fiction: language, heroes and setting. Niclas Salomonsson, a literary agent who represents almost all the up and coming Scandinavian crime writers, reckons it is the style of the books, “realistic, simple and precise…and stripped of unnecessary words”, that has a lot to do with it. The plain, direct writing, devoid of metaphor, suits the genre well.

The Nordic detective is often careworn and rumpled. Mr Mankell's Wallander is gloomy, troubled and ambivalent about his father. Mr Indridason's Inspector Erlendur lives alone after a failed marriage, haunted by the death of his younger brother many years before in a blizzard that he survived. Mr Nesbo's leading man, Inspector Harry Hole—often horribly drunk—is defiant of his superiors yet loyal to his favoured colleagues.

Most important is the setting. The countries that the Nordic writers call home are prosperous and organised, a “soft society” according to Mr Nesbo. But the protection offered by a cradle-to-grave welfare system hides a dark underside. As Mary Evans points out in her recent study, “The Imagination of Evil”, the best Scandinavian fiction mines the seam that connects the insiders—the rich and powerful—and the outsiders, represented by the poor, the exploited and the vulnerable. Larsson is a master at depicting the relationship between business, social hypocrisy and criminal behaviour, and his heroes do not want to be rescued through any form of conventional state intervention.

Analysing Scandinavia and its psyche is nothing new; Henrik Ibsen did it over a century ago. But the greatest influence on these rising writers has been Per Wahloo and Maj Sjowall, a Swedish couple. Journalists and committed Marxists, they coauthored the ten-volume Martin Beck series between 1965 and 1975 with the aim of criticising the country's welfare state. The central character is a likeable and dedicated policeman with a dry sense of humour. But the books, which closely study police procedure, feature an ensemble of his colleagues, all believable characters drawn with the lightest of touches. By turn entertaining and funny examinations of the day-to-day work of policemen, they are also gripping and complex thrillers.

The quality and popularity of crime fiction has given Nordic novelists a prestige that authors from other countries do not enjoy. This, in turn, has drawn in new writers. The next potential blockbuster could well be Leif G.W. Persson's “Fall of the Welfare State”—though a more enticing title is planned for its English-language debut. First published in Sweden in 2002, it is written by a professor of criminology who has been involved in many of Sweden's high-profile crime cases and is an epic and ambitious tale spanning several decades of Swedish history.

The cold, dark climate, where doors are bolted and curtains drawn, provides a perfect setting for crime writing. The nights are long, the liquor hard, the people, according to Mr Nesbo, “brought up to hide their feelings” and hold on to their secrets. If you are driving through Norway at dusk and see a farmhouse with its lights on and its doors open, do not stop, he warns, only half jokingly. You are as likely to be greeted by a crime scene as a warm welcome.