What’s the difference between a crime novel, a mystery and a thriller?

Here’s what I learned from a little research (many thanks to Writer’s Digest):

These focus on solving a crime — usually a murder. The story is about who committed the crime and why and getting some type of justice.

Mysteries are all about sorting the truth from the lies, the significant from the insignificant and the innocent from the guilty. The solver of the crime may be a cop,  a private investigator, a reporter or an amateur sleuth. The crime might be an accident, a vendetta or a staged ritual.

In a murder mystery, the crime is always covered up and the villain always attempts to deceive and escape justice. Heroes in these books are strongly motivated to see justice done; they may have a code of ethics that guides them. They have well-developed powers of observation and reasoning, but they also have empathy.

Within the mystery novel category are:

• Cozy mysteries. These books avoid hot sex and graphic violence. They tend to take place in tranquil or ordinary settings — villages, shops or craft cruises, for example. The sleuth is an amateur — sometimes with mystery-solving experience, sometimes without — and tends to be an engaging character. An example is Laura Childs’ Keepsake Crimes, which are solved by the owner of a scrapbooking shop.
• Hard-boiled mysteries. These mysteries are solved by experienced, professional, seen-it-all detectives, cops or private eyes. The stories involve violence and often sex. The heroes survive on mean streets, but hold on to their empathy or sense of justice and fairness in an unfair world. Think of Raymond Chandler’s Philip Marlowe or Lee Child’s Jack Reacher. Zöe Sharp’s Charlie Fox fits this mold. Michael Connelly’s character Harry Bosch certainly fits in this category.
• Police procedurals. This type of mystery novel is all about the process by which law enforcement goes about solving a crime. Examples include Robert Bryndza’s The Girl in the Ice featuring Detective Chief Inspector Erika Foster, or Susie Steiner’s Missing, Presumed, featuring Detective Sergeant Manon Bradshaw. Maurizio De Giovanni’s Commissario Ricciardi stories fit this category well. Tana French’s Dublin Murder Squad books could be called police procedurals, but they tend to have much more psychological depth than the average police procedural.
• Medical, scientific or forensic. These are similar to police procedurals, but the tools and expertise used to solve the crime are weilded by doctors, scientists or medical examiners.
• Legal or courtroom dramas. Here justice is achieved in the courtroom. An example of using the law in a twisted way to get justice is Scott Pratt’s novel, An Innocent Client. Of course, John Grisham is the quintessential author of legal dramas.
• Noir novels. These books have a dark atmosphere and heroes who are compromised morally or by past behavior, ethics, addictions or profession. Philip Kerr’s novels featuring former policeman turned private investigator Bernie Gunther are good examples. Trying to stay afloat in Berlin during the Nazi era, Gunther is repeatedly tempted, required or forced into partnership with the Nazis to solve his clients’ dilemmas. Scandanavian writers are famous for “nordic noir.” You might even classify Jane Harper’s Australian mystery, The Lost Man, as a noir mystery because making things right in this world involves committing a wrong.

Crime Novels

These novels focus on the war between good and evil as shown by the detective (usually a member of law enforcement) and the villain. Crime novels are all about the pursuit of justice on behalf of the victim.

Crime novels tend to open with a crime and the reader knows at least pieces of the perpetrator’s identity.

The mystery isn’t so much the point here as the escalating suspense about whether the detective will capture the criminal before another crime is committed. An example, although not a typical one, is The Dying Detective by Leif G. W. Persson. John Sandford’s Prey Series are good examples of crime novels. Emma Flint’s book Little Deaths, fits well because it revolves around a crime and the slender evidence used to convict a woman.

Writer’s Digest describes this genre as a hybrid of mystery and horror. Thrillers tend to be high suspense and involve crimes with high stakes — the safety of the world or preservation of national or historical treasurers.

The threat of even worse crimes than the one that launched the story haunts the protagonist until the climax. The villain may have a grudge against the protagonist because of past history or a particular vulnerability.

Think Alfred Hitchcock’s movies here.

A classic thriller where the villain has been pursuing the victim for virtually a lifetime is Dan Fesperman’s Safe Houses.

Within the thriller category, you’ll find epic thrillers that involve communities, cities, countries or the world; psychological or suspense novels, where the scale of the story is more intimate and the threat focuses on the protagonist or those whom he or she holds closest; or the supernatural thriller, where both or either the protagonist or the villain have supernatural powers.

Yiftach Reicher-Atir’s thriller The English Teacher is not quite epic but it does have peace in the Middle East at stake when a retired Israeli spy goes rogue for personal reasons. Patricia Cornwell graduated evolved her Kay Scarpetta mysteries from solving local crimes to pursuing arch criminals who threatened world peace.

Kem Nunn’s Chance is the perfect example of a psychological/suspense novel where a highly ethical but naive protagonist is pitted against a horrific villain.

Patricia Briggs’ urban fantasy novels featuring Mercy Thompson, a shape-shifter married to a wereworlf, are supernatural thrillers.