A good detective series depends on the author’s ability to devise canny plots with attendant clues and blind alleys, but of greater importance is the central detective who acts as a charismatic guide through the miasma of murder and mystery. There are many compelling detectives in crime fiction: think of Inspector Maigret, Hercule Poirot, Adam Dalgliesh, Kay Scarpetta and Stephanie Plum. However, with the exception of Sherlock Holmes and Dr Watson, and, more recently, Stieg Larsson’s Lisbeth Salander and Mikael Blomkvist, memorable couples are rare in the sleuthing game.