Here is a list of concepts and conventions found in Golden Age detective fiction, along with representative titles where appropriate.
Fair play rules are meant to benefit the reader. The idea is that readers should be able to solve the crime along with the detective, if their wits are sharp enough. The rules of fair play prevent the author from throwing in unforeseen surprises that would prevent readers from solving the mystery themselves. Basically the rules state that there must be no bizarre breaks or surprise solutions that are hidden from the reader until the end and that the reader must be in possession of all the clues; nothing should be withheld by the author. Here is a short summary of the rules, taken from Julian Symon’s The Detective Story in Britain:
*these had become laughably unlikely solutions to crimes in novels and stories of lesser quality before the adoption of the rules of fair play.
A mystery taking place in the country and at a private residence, usually a grand country manor. The crime nearly always occurs during a weekend house party (what better way to involve multiple suspects?) and with either a professional or amateur detective in attendance. The entire story is usually confined mainly to the house and its grounds and if anyone runs up to London (usually the detective, in order to check records or to have evidence tested) or goes into the local village it is only briefly mentioned. Quite often, particularly in Christie’s work, the detective returns to the house prepared to unmask the criminal in front of a pre-assembled audience.
According to the “Rules of the House” set down by Thomas Godfrey, the house itself must have character (whether pleasant or dreary), ought to have some secrets and maybe even reports of ghosts, needs at least a few servants to vouch for people’s whereabouts at the time of the crime and should have an unreliable telephone system (Godfrey, 1995, p.xv). These are some of the conventions that bring pleasure to the reader, even in the face of murder.
Examples: The Red House Mystery by A.A. Milne, Murder for Christmas by Agatha Christie, Police at the Funeral by Margery Allingham. I personally enjoy those country house mysteries that take place in winter with a crackling fire in the grate and an abundance of snow on the ground.
A murder that occurs in a locked room or place with no visible mode of egress for the murderer. It seems impossible that the murder could have been committed because there are no signs of human activity around the body and no way out of the room. It seems supernatural to most observers but for the expert detective it is fully rational and deducible. This convention was a great favorite of John Dickson Carr, who used it in many of his novels. One of his most creative uses of the locked room mystery is found in The Problem of the Wire Cage. The body in this novel is not found in a room but on a fenced-in tennis court.
A mystery that contains contradictions and seemingly inexplicable aspects. The paradox goes hand in hand with the impossible crime. The work of G.K. Chesterton best embodies the paradox.
Examples: The Innocence of Father Brown, The Paradoxes of Mr. Pond, The Club of Queer Trades , all by G.K. Chesterton.
A mystery not involving a murder but rather a puzzling circumstance that must be reasoned out.
Example: Gaudy Night by Dorothy L. Sayers
Is a plot that is conceived so that the reader sees the criminal and sometimes the occurrence of the crime and follows the detective as he or she pieces together the events, or “where the perpetrator is known and the method of discovery occupies the reader” (Godfrey, 1995, p.95). R. Austin Freeman is an innovator of this type of story.
Examples: The Singing Bone by R. Austin Freeman, The Stoneware Monkey by R. Austin Freeman.