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 Act of God?
Other codes, such as the Ten Commandments of Ronald Knox, or the Twenty Rules of S. S. Van Dine were promulgated during the Golden Age, with varying degrees of seriousness. Many of my favorite stories thumb their noses at the classic rules and are none the worse for wear. Which makes sense, for transgression is the heart of a crime story.
For me, these are the three deadly sins of mystery stories. I have read many stories that make these choices (aka fatal errors), and it never fails to spoil my enjoyment:
- A detective who doesn’t detect. This is a pet peeve of mine in many contemporary “cozy” mysteries. If the supposed sleuth is actually just bumbling along making a nuisance of herself (and let’s face it, this type is usually written as a woman), until the villain tries to bump her off – that is not an investigation. That is the intellectual equivalent of poking a stick into an anthill to see what comes to bite you. The murderers in this type of story seem to be even stupider than the soi-disant detectives, as it is obvious that they would never be found out if they kept quiet, and their adversary is incapable of obtaining any real proof against them. I recall one particularly egregious example of this type, in which even after the murderer revealed himself, there was exactly zero evidence to convict him of anything other than attempting to murder the sleuth-he didn’t even confess to the original crime! For all I could see, the killer in the last chapter may have assaulted the busybody out of sheer annoyance. The person who recommended that item to my attention went on my short list.
- A plot that relies on open and notorious stupidity (see above). A good detective, like a good tennis player, may manipulate circumstances to force his opponent into an error. And many strong tales hinge on the one subtle mistake that gives the villain away in the end. But plots that I have to explain to my four-year old by saying, “because if they did that, there would be no story, honey…”? Pfffft.
- Madness without method. The crazed serial killer is a popular figure in contemporary crime tales, but this in my mind is an entirely separate genre and should remain so. While insane murderers show up from time to time in the classics (Christie’s The Thumb Mark of St. Peter and Endless Night come to mind), even they are pushed into action by a comprehensible motive – gain, self-protection, revenge. Forensic psychology is fascinating to some, but when I enter the world of a mystery, I don’t want to wind up inside a psychopath’s head.
What makes a mystery satisfying to you? Which rules are deal-breakers in your mind? What rules do your favorite authors break with impunity?