There really must be a murder, or at least a major felony — otherwise, what’s the point? Who’s ripping off the hand towels at the Dorchester Hotel is hardly the business of a mystery novel.

— Howard Haycraft

When I say I am a novice writer, people ask, “What kind of books do you write?”

“Well,” I answer, “I’m writing a mystery.”

“Ooh,” they often reply, “I love Agatha Christie.”

While it’s not exactly a bullseye, it’s a good place to start the conversation.

For many readers, a mystery is a mystery. Someone dies, someone is to blame, and, within two hundred pages or so, someone — usually someone wearing a deerstalker hat or sporting a fantastic mustache or assessing various suspects over tea at the village social — connects the dots. Nice, tidy and a bit predictable.

Now what I’ve just described would likely fall into the mystery sub category of a whodunnit. Or perhaps a cozy mystery, given the setting and the protagonist. So, is there really a difference?

Well yes, there is a significant difference. In fact, there are all kinds of mystery novel genres, each with its own rules, traditions and expectations. These rules can be flexible, but they give the reader a general idea of what to expect when someone picks up the book (or the iPad, or the Kindle or the Nook).

For today’s blog, I’d like to give you a brief overview of some of my favorite sub-genres. And keep in mind, these are just a few of my favorites. Also, if you have a clear favorite already, be kind. The lines between one genre and another may blur at times, so what I’ve categorized as a police procedural, you may consider a Hard-Boiled Detective book. It’s all in the eye of the individual reader.

First up on our mystery tour, there’s the classic Whodunit? These are what most people probably think of when they think “mystery.” As I mentioned a few moments ago, you’ve got a murder, and someone solves it. In the Whodunnit? That person is most likely a consulting detective. Think Sherlock Holmes, Hercule Poirot or Nero Wolfe — even more modern characters like Precious Ramotswe and Veronica Mars. They aren’t cops, but they are the ones the cops call when the mystery gets too mysterious. For the reader and the author, this trope lends a bit of flexibility to the tale. As someone acting outside the confines of the police force, he or she doesn’t always have to play by the rules. In fact, it’s often more fun when they don’t.

If you start with a consulting detective and then give the protagonist a soul-crushing backstory, your hero (or anti-hero as the case may be) may have evolved into a Hard-Boiled Detective. First popularized during the mob-era 1930s and 1940s, these are from classic noir books where the lines between the white hat and the black hats have blurred. Authors like Dashiell Hammett, Raymond Chandler and James M. Cain were early masters of the genre. In their bleak, grimy worlds, the action is gritty, morally ambiguous and, honestly, kind of depressing. The modern generation of noir authors includes James Ellroy, Philip Kerr and, my personal favorite, John Connolly, who seamlessly blends the hard-boiled detective archetype with themes of horror and the occult.

Check back in two weeks and we’ll look at four other classic mystery types, including two that have made surprising comebacks in the past few years.

So, what are your questions and comments on murder mysteries? What’s your favorite type of fatal fiction? Drop me a line — I’d love to hear from you.

Love a good murder? Be sure to take a stab at Thou Shalt Not Kilt, a traditional Southern cozy with Scottish flavor. For my latest news and book updates, follow me on Instagram and Facebook, and sign up for Mondays Are Murder, my weekly mystery newsletter — plus, you’ll get a free downloadable copy of Masters of Murder, my guide to the detectives and authors of mystery’s Golden Age!