What makes a good mystery? A seemingly simple question, but the answer is not so simple.
In 1928, Father Ronald A Knox, Roman Catholic priest, mystery writer, and one of the founders of The Detection Club, set forth the rules for fair play for detective fiction, known as Knox’s “Ten Commandments” or the “Decalogue.”
1. The criminal must be mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to know.
2. All supernatural or preternatural agencies are ruled out as a matter of course.
3. Not more than one secret room or passage is allowable.
4. No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
5. No Chinaman must figure in the story.
6. No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
7. The detective himself must not commit the crime.
8. The detective is bound to declare any clues which he may discover.
9. The stupid friend of the detective, the Watson, must not conceal from the reader any thoughts which pass through his mind: his intelligence must be slightly, but very slightly, below that of the average reader.
10. Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.
These rules guided mystery writers during the Golden Age of detective fiction and were distilled into the oath sworn by the initiates into the exclusive, invitation-only Detection Club. During the ceremony, the initiate would be asked to swear on Eric the Skull the following:
Do you promise that your detectives shall well and truly detect the crimes presented to them, using those wits which it may please you to bestow upon them and not placing reliance on nor making use of Divine Revelation, Feminine Intuition, Mumbo-Jumbo, Jiggery-Pokery, Coincidence or the Act of God?
Detectives in mystery novels rarely changed during the Golden Age. As Dorothy Sayers put it her essay, “Gaudy Night,” The Art of the Mystery Story, 1946, 1974, 210-211.
I plugged confidently on, putting my puppet [Lord Peter Wimsey] through all his tricks and exhibiting him in a number of elegant attitudes. But I had not properly realized—and this shows how far I was from understanding what it was I was trying to do with the detective novel—that any character that remains static except for a repertory of tricks and attitudes is bound to become a monstrous weariness to his maker in the course of 9 or 10 volumes. . . . If the story was to go on, Peter had got to become a complete human being.
Change was inevitable. The rules were simply too constricting. One by one the rules were broken. And in 1973, Josef Skvorecky, in a collection of short stories, deliberately broke all ten rules in Sins for Father Knox.
The reader can expect to find a central mysterious death, a closed circle of suspects each with credible motive, means and opportunity for the crime, a detective, either amateur or professional, who comes in like an avenging deity to solve it, and a solution at the end of the book which the reader should be able to arrive at by logical deduction from clues presented by the writer with deceptive cunning but essential fairness.
For me, the key elements in what makes a good mystery are these:
• An engaging detective
• A puzzle I can solve
• Interesting characters
• A great setting
• And most of all storytelling so powerful that the world of the mystery becomes the world I live in while the real world vanishes—whether it’s the wacky world of Janet Evanovich, the racing underworld of Dick Francis, the violent world of Michael Connelly, or the English upper-class world of Agatha Christie.
What are the key elements for you?