Types of Mysteries
There are four major types of mysteries. Within each category, there are sub-categories (like paranormal or historical).
A mystery must have certain elements to be considered a mystery. Essentially, a mystery will have a puzzle or secret, or layers of puzzles or secrets, a setting that fits the type of book, a sound motive, red herrings, and clues.
Most traditionally accepted mysteries have a murder. This is the element that compels people to keep reading. While some mysteries may not have a murder (or murders) at the center, the majority do. If you don’t have a murder, you may be writing a suspense. Something to think about.
There are four major types of mysteries within the broad genre. Within each category, there are sub-categories.
A mystery must have certain elements to be considered a mystery. Essentially, a mystery will have a puzzle or secret, or layers of puzzles or secrets, a setting that fits the type of book, a sound motive, red herrings, and clues.
Cozy
Traditional cozies have a likable amateur sleuth. Violence, gore, and sex generally happen off page. They are set in tight-knit communities and the sleuth is surrounded by a tight-knit group of people. There is a series arc which allows the sleuth to grow and change and develop within the community and relationships. And there is a murder with a puzzle for the sleuth and the reader to solve. The sleuth falls into the mystery by accident or circumstance and uses common sense/gray cells to solve the crime. Cozies are most often told in first person point of view. Agatha Christie is the grande dame of the genre.
Hard-Boiled
The hardboiled mystery is a detective story with attitude and action. It’s a tough mystery that takes place in a city or urban setting. It’s gritty. It’s violent. The blood and violence (and sex) takes place on the page. Usually the detective is a professional who’s been hired to investigate. A hard boiled mystery is most often told in first person with a bare-bones or abrupt narrative style. This is not your emotional mystery. Think Raymod Chandler or Michael Connelly, as well as Kinsey Milhone, a loner ex-cop PI.
Soft-Boiled
The soft boiled mystery falls somewhere between the hard boiled and the cozy. It’s not as violent as the hard boiled, but not quite as clean as a cozy. Many soft-boiled mysteries have humorous elements. The detective can be a professional or amateur, and is usually a woman. The setting tends to be in bigger cities (versus the small town setting of the cozy). Janet Evanovich’s Stephanie Plum books are soft boiled (with some caper thrown in).
Police Procedural
The detective/sleuth in a police procedural is almost always a law enforcement agent of some sort. The details of the mystery plot are the focus, as opposed to the heavier character development of the other categories. The term police procedural is used because the procedures are detailed and accurate. Rules must be followed and crime details are key. PD James Adam Dalgliesh and Michael Connelly’s Harry Bosch series.
Beyond these four standard categories, you can drill down into private investigator novels, historical mysteries, romantic suspense, psychological, political, and legal thrillers, paranormal, westerns, and even SciFi.
Think hard about the kind of details, pov, setting, level of violence in your book and how to categorize it. Not every book fits neatly into a category, but you should be able to see it in one of these categories (even if you have to push or shove a little bit!). Just a caveat, things that aren’t easily marketable–meaning your agent or editor doesn’t know how to explain what it is–are less likely to sell. If you can categorize your book, in general, all the better.