I’ve read a lot of lists of rules for mystery writers. Everyone wants to tell us what to do, but I’ve discovered by reading through these lists that large swathes of them are either misguided or simply false. So this is my set of casual guidelines for mystery writing—to steer you in the right direction but also to remind you to think for yourself.
The plot is not everything in mysteries, as so many of these lists of rules say. Just having a lot of action or clues and red herrings doesn’t make a good crime novel. The best plots rise out of character. Dive deep into your major characters and discover their motivations and their secrets. Your best plot with all its twists and turns will come from the fears, desires, and manipulations of your characters and how many of them are at cross-purposes with each other.
Introduce both the protagonist and the antagonist early on. This is important—for any novel. The reader needs to know with whom to identify and who is threatening whatever that protagonist with whom he identifies is trying to achieve.
The crime needs to be a major crime, preferably murder, but there have been successful mysteries written around art heists, con schemes, and other crimes. In Gaudy Night, Dorothy Sayers even wrote one of the classic novels in which only anonymous letters and vandalism occur. You must simply be able to make it of absolute importance to the protagonist and to the reader. Murder is not required—it’s just easier.
The crime and its solution should seem believable. The reader must be able to believe that the antagonist could commit whatever heinous crime you’ve given him and that the protagonist could solve it and overcome him. Physically, intellectually, and emotionally, the crime must seem possible to the reader without giving either the villain or the hero superpowers.
And as a corollary to this—you must motivate your villain. Because he or she is pure evil or stark raving mad is not a good reason to break major societal taboos and put himself or herself in danger of life in prison or the death penalty. As much as you motivate your other characters to make them believable, so much must you motivate your antagonist to make a credible threat. The more complex and motivated the villain, the more memorable and fascinating.
One of these rule lists sets as an adamant, must-obey rule that your narrator or detective must never commit the crime. Hello? Does anyone remember a little-known writer like Agatha Christie who violated that rule in three different, very successful books? If you want to make your narrator or detective commit the crime, you will have to be fiendishly clever to pull it off, but if you are and can, go for it!
One of the rules in almost every list that I will agree with is the admonition to do your research. I know a writer who came from another genre to mystery and doesn’t like research so he makes things up. That will come back to haunt you in mysteries. Mystery readers expect and demand good research so that they can stay in the fictive dream. They will chastise you in a minute (and rightly so) if they catch you in a factual error—and there is always someone, and usually more than one, who will catch you. On the other hand, they reward those who research and use it well with great loyalty. Do your research and learn how to use it so it doesn’t stop or slow the story.
So, these are my casual guidelines for mystery writers. Nothing is written in stone. Every writer is a different situation. Some may even be able to introduce protagonist and/or antagonist over halfway through the book. I know I couldn’t, but that doesn’t mean you can’t. It’s just much easier to keep your reader’s interest, however, if you introduce them both in the first few chapters. Every other guideline I’ve given is the same. Perhaps you are so brilliant at making things up that no one will ever question your lack of research. I wouldn’t count on it, but it’s always possible. Use these as guidelines for your own judgment. Ultimately, it’s your book. You are the creator and need to do it your own way. Just make sure that your readers will follow you along your book path.