In publishing Pick Your Victim (1946), the American novelist Patricia McGerr devised a new category of detective fiction, in which the central interest lies in discovering the identity of the victim. Earlier novels in which an unidentified body is found Whose Body? (1923) by Dorothy L. Sayers is, as its title indicates, an example had fallen broadly within the existing conventions, but McGerr broke new ground. A group of Marines discover a torn newspaper clipping which reveals that Paul Stetson has admitted killing a colleague; however, the name of his victim is missing. One member of the group had worked with Stetson and the bored men while away time by listening to his account of the personalities involved and trying to guess whom Stetson strangled. The mystery is solved through psychological understanding: Stetson was a potential murderer only because one particular co worker was a potential victim. The originality of Pick Your Victim was immediately recognised; in A Catalogue of Crime Jacques Barzun and Wendell Hertig Taylor christened it a whowasdunin? McGerr adopted a similar approach in The Seven Deadly Sisters (1947), but included a mystery about the identity of the killer as well as of the victim. In her fifth novel, Follow, As The Night (1950; Your Loving Victim) she again returned to the whowasdunin? before concentrating on more orthodox stories.

As interest has increased in the motivations that can drive one human being to murder another, the possibilities of this type of novel have become apparent but so have its drawbacks. Typically, the book will begin with a description of a victim’s death or the discovery of a corpse and a flashback will follow in which the events leading up to the crime are described in detail before the final disclosure (which may or may not occur as a result of shrewd detective work) of the victim’s identity and often also that of the culprit. The danger is that the pace may flag and so writers employ a range of plotting techniques in order to maintain reader interest.

The Man Who Didn’t Fly (1955) by Margot Bennett is a clever variation on the basic theme. Four men were due to board an aeroplane, yet only three did so; when the plane crashes into the sea and the bodies cannot be recovered, the police must establish who the fourth man was and why he did not fly. Bennett intersperses with the flashbacks short chapters set in the present and thereby manages to keep the central mysteries clear in the reader’s mind without sacrificing momentum. Writing as Barbara Vine, Ruth Rendell has shown the flexibility of the whowasdunin? as providing a structural framework for novels of unquestioned literary excellence. A Fatal Inversion (1987) starts with the discovery of a human skeleton in an animal graveyard; blending scenes from past and present with the utmost skill, Vine creates almost unbearable tension. Julian Symons’ under-rated late novel, Something Like A Love Affair (1992), begins when an old man reports the discovery of a body without identifying its sex. Symons then combines a perceptive study of the disintegration of a woman’s life with brief references to the continuing police enquiries, before revealing culprit, victim and motive in a startling climax. The continuing popularity of the whowasdunin? is shown by Robert Richardson’s The Hand Of Strange Children (1993). His method is to interweave extracts from news agency reports detailing the discovery of two bodies with flashbacks told in both the first and third person. Again the careful judgement of time shifts contributes to the building of suspense. By treating the apparent limitations of the whowasdunin? as a challenge to their wits, writers have transformed it into one of the most effective of all forms of mystery fiction.

(An earlier version of this article originally appeared in The Oxford Companion to Crime & Mystery Writing edited by Rosemary Herbert)