Mystery fiction encompasses a broad spectrum of subgenres, although it is common for casual aficionados to focus on the detective story as the only “true” mystery. As I have often defined it (and, quite naturally, I regard it as a good and fair definition), a mystery is any work of prose fiction in which a crime or the threat of a crime is central to the theme or plot.
On a football field, the pure detective story may go from the end zone to the twenty-five-yard line. The crime story, in which the central figure is a criminal of some kind, whether rogue or villain (and I’ll get to that shortly), may move the ball another twenty yards. The novel of suspense, which includes women or children in jeopardy, the everyday gone wrong, as well as tales of psychological unease and irrational behavior, whether of sociopathy or fear, will produce a long gain well past midfield, and espionage/international intrigue will cross the goal line. The killing of a large number of people is, of course, part of the same horrific game as the killing of an individual.