Retracing these journeys, I have made a 15-part series for BBC Radio 4, Foreign Bodies, which uses celebrated fictional detectives — from Christie's Poirot to Nesbø's Harry Hole — to explore the history of modern Europe. Cop novels are a useful tool for such a survey because the police procedural turns on detail. Novelists working in crime-free narratives have no need (and often no wish) to specify a character's job, clothes, income or family background. But because observation and evidence are crucial to the investigation of a crime – the motive for which will often rest on who someone was or what they possessed or desired – crime writers routinely provide a mass of social detail: menus, train timetables, fashion labels, shops, newspaper stories. As a result, good crime novels become a case-file of their times. The introduction of the welfare system and unemployment benefit, for example, can be traced through the comments of posh employers in Christie's mysteries. And reporters preparing to cover the impending referendum on Scottish independence would be well advised to read Ian Rankin's DCI Rebus books, which systematically depict the country's re-examination of its identity over the last 25 years.
I think this goes some way to explaining the mass appeal of crime novels. Some say we read in order to live other lives. Reading crime novels then, with their finer level of detail, may be a more immersive experience (whether for the purpose of education, entertainment, or escape).
(Certainly the attraction to my latest criminal addiction — Marek Krajewski — has less to do with the police case at hand than it does with the minutiae of 1930s Poland: the meals, the bars, the beer and the vodka, office life, marriage bureaus, tenements. All reliably filtered through an investigator who, though he often breaches ethics and good taste, has the mental discipline of a chess enthusiast and a Latin scholar.)
While Sherlock Holmes remains the detective archetype, Lawson identifies Georges Simenon (and his creation, Maigret) as the greatest influence on European crime fiction:
In Rome, Andrea Camilleri — creator of the Sicilian policeman Inspector Montalbano — pointed out to me the complete set of Maigret books on his shelves. In Berlin, one of the leading German crime-writers, Jakob Arjouni, also kept a complete Simenon close to his desk. PD James cites Simenon as a master as well, confirming a literary afterlife that perhaps validates the view of André Gide that the Belgian writer should have won the Nobel prize for literature.
Perhaps because Simenon expresses more temperament, and Maigret acts on instinct — the approach to crime is more believable than that taken by Doyle, more "human" than Holmes. My fascination with Simenon's books is by now well documented, and continually being validated.