Many people jumble these genres and their sub-genres up. In this piece for Writers Digest, David Corbetts, the award-winning author of five novels, draws the lines clearly for both writers and readers.

The suspense genres in particular have a number of seemingly hard and fast rules that a writer defies at his peril. And yet the most satisfying mysteries, thrillers and crime stories find a way to create a new take on those rules to fashion something fresh, interesting, original. Here’s a map to help you navigate subgenre subtleties.

Mystery Novels

By definition, a mystery is simply something that defies our usual understanding of the world. In a mystery novel, a crime is committed—almost always a murder—and the action of the story is the solution of that crime: determining who did it and why, and obtaining some form of justice. The best mystery stories often explore man’s unique capacity for deceit—especially self-deceit—and demonstrate a humble respect for the limits of human understanding. This is usually considered the most cerebral (and least violent) of the suspense genres.

Thematic emphasis: How can we come to know the truth?

Structural distinctions: The basic plot elements of the mystery form are:

  • The baffling crime
  • The singularly motivated investigator
  • The hidden killer
  • The cover-up (often more important than the crime itself, as the cover-up is what conceals the killer)
  • Discovery and elimination of suspects (in which creating false suspects is often part of the killer’s plan)
  • Evaluation of clues (sifting the true from the untrue)
  • Identification and apprehension of the killer.

Additional Reader Expectations:

The Hero: Whether a cop, a private eye, a reporter or an amateur sleuth, the hero must possess a strong will to see justice served, often embodied in a code (for example, Harry Bosch’s “Everyone matters or no one matters” in the popular Michael Connelly series). He also often possesses not just a great mind but great empathy—a fascination not with crime, per se, but with human nature.

The Villain: The crime may be a hapless accident or an elaborately staged ritual; it’s the cover-up that unifies all villains in the act of deceit. The attempt to escape justice, therefore, often best personifies the killer’s malevolence. The mystery villain is often a great deceiver, or trickster, and succeeds because she knows how to get others to believe that what’s false is true.

Setting: Although mysteries can take place anywhere, they often thematically work well in tranquil settings—with the crime peeling back the mask of civility to reveal the more troubling reality beneath the surface.

Reveals: Given its emphasis on determining the true from the untrue, the mystery genre has more reveals than any other—the more shocking and unexpected, the better.

Mystery Subgenres

➤ Cozy: One of the ironic strengths of this subgenre is the fact that, by creating a world in which violence is rare, a bloody act resonates far more viscerally than it would in a more urban or disordered setting.

Reader Expectations: A unique and engaging protagonist. The crime should be clever, requiring ingenuity or even brilliance on the hero’s part to solve. Secondary characters can be coarse, but never the hero—or the author. Justice triumphs in the end, and the world returns to its original tranquility.

➤ Hard-boiled: The hero is a cop or PI, tough and capable. The moral view is often that of hard-won experience in the service of innocence or decency. The hero tends to be more world-weary than bitter—but that ice can get slippery.

Reader Expectations: A strong hero who can “walk the mean streets but who is not himself mean,” as Raymond Chandler once put it. The style is often brisk and simple, reflecting the unpretentious nature of the hero, who is intelligent but not necessarily learned.

➤ Police Procedural: A cousin to the hard-boiled subgenre, with the unit or precinct taking over for the lone cop.

Reader Expectations: Much like the hard-boiled detective story, but with a larger cast and special focus on police tactics, squad-room psychology, station-house politics, and the tensions between the police and politicians, the media and the citizenry.

➤ Medical, Scientific or Forensic Mystery: A refinement of the police procedural in which the protagonists—doctors, medical examiners, forensic pathologists or other technical experts—use intelligence and expertise, not guns, as their weapons.

Reader Expectations: Similar to the police procedural, with extra emphasis on the physical details of analyzing unusual evidence.

➤ Legal or Courtroom Drama: The crime is seen through the eyes of the lawyers prosecuting or defending the case.

Reader Expectations: A meticulous rendering of criminal court procedure and politics, along with how police and prosecutors work together (or don’t).

 

Crime

In this genre the focus is on the contest of wills between the lawman hero and the outlaw opponent, and their differing views of morality and the aspects of society they represent. The greatest crime stories deal with a moral accounting on the part of the hero for his entire life, or provide some new perspective on the tension between society and the individual.

Thematic emphasis: What is a just society? The story world of the novel is out of balance, somewhere between a state of nature (where chaos prevails and those with money and/or guns wield power) and a police state (where paranoia prevails and the state monopolizes power). The hero hopes in some way to rectify that imbalance.

Other moral themes can include the challenge of decency, honor and integrity in a corrupt world; individual freedom versus law and order; and the tension between ambition and obligations to others.

Structural distinctions: There is seldom any “mystery” as to who the criminal is. Typically the story starts with a brilliant or daring crime, and then a cat-and-mouse game of wits and will ensues, with the tension created by the increasing intensity of the battle between the opponents. The underlying question is: Will the cops prevail before the opponent stages his next crime?

Given the similarity to war and action stories, the prose often tends toward the naturalistic.

Additional Reader Expectations:

The Hero: Usually a tough and capable cop (or vigilante) who believes in the society she defends despite its flaws, the crime fiction hero is often seen as an outcast but is revealed to be the most morally engaged character in the story.

The Villain: Routinely a tough and brilliant criminal who considers the system rigged and the society inherently flawed, he is often a kind of Luciferian rebel—the rogue individual par excellence—even if he commands a crew or organization.

Setting: This genre gravitates toward urban locales, but suburban, rural and even wilderness settings have all been used to great effect. Let the setting ground the moral theme.

Reversals: Just as the mystery genre, by focusing on the search for truth, obliges numerous reveals, the crime genre, by focusing on battle, obliges numerous reversals—with the hero and the villain trading knockout blows and suffering serious setbacks to their respective plans.

 

Thriller

Where mystery stories represent the most cerebral of the three major suspense genres, and crime stories the most dramatic, thrillers are typically the most emotional, focusing on the fear, doubt and dread of the hero as she faces some form of what Dean Koontz has deemed “terrible trouble.” This genre is a hybrid of mystery and horror. However, the thriller also shares a literary lineage with the epic and myth. Monsters, terror and peril prevail.

Thematic emphasis: The dangerous world we live in, the vulnerability of the average person, and the inherent threat of the unknown.

Structural distinctions: The plot often proceeds along these lines:

A devastating crime is about to be committed, or has been committed with the threat of an even worse one in the wings.

The perpetrator is known, but his guilt is not absolutely certain—or the hero wishes not to accept the truth of his guilt. (The uncertainty enhances the suspense.)

The hero is under constant attack as she tries to definitively prove the perpetrator’s guilt and/or stop the next atrocity.

Additional Reader Expectations:

The Hero: Given the relentless attack the villain inflicts, and the emphasis on terror and dread, the thriller hero must be vulnerable—not just physically but psychologically.

The Villain: In the best thrillers, the villain either targets the hero specifically from the outset or learns through the course of the story what his particular weaknesses and wants are, and targets them for ruthless attack.

Setting: Whether as small as a cottage in the woods or as large as the planet, the world the hero seeks to protect represents everything she values. The stakes are ultimate.

Thriller Subgenres

➤ Epic Thriller: This usually concerns the threat of some catastrophe affecting whole communities, cities, countries, even the planet. The threat need not be total devastation—the assassination of a leader will do—but the effect of the action must be profound.

The villain can be a terrorist, a diabolical genius, or an ordinary person with an oversized grudge and a unique capacity for damage.

Given the scope of the threat, the protagonist must possess the skills to defeat the villain, and thus is often a soldier, a spy, a trained assassin, a cop, or a civilian with a special skill set. The action is brisk, even nonstop, and the climax needs to be both thoroughly foreshadowed (we need to know the basic parameters of the threat all along, and the measures being taken to stop it) and unexpected (plot twists are not optional—they’re required). This is a pull-out-all-the-stops genre.

➤ Psychological Thriller/Suspense: Here the threat is still diabolical but more contained, even intimate—usually targeting the protagonist and/or his family—and the hero is often a relatively “ordinary” man, woman or child. The pacing is a bit more deliberate, to reflect the ordinary person’s difficulty understanding the exact nature of the threat—and the enemy—and then struggling to respond. The third act, however, moves briskly.

➤ Supernatural Thriller: This subgenre is something of a hybrid, in that the nemesis presents an overwhelming threat—he might be Satan himself—and yet that threat is often focused on a single soul or a mere few, rather than the whole of mankind, at least within the story.