The Delaware Valley Sisters in Crime (DVSinC) mystery / crime writers and readers group (serving the Philadelphia area, southern New Jersey, and Delaware) is an organization devoted to readers and writers of all types of mystery and suspense literature.  The literature has been divided into many sub-genres, and new ones are created all the time, but some of the most widely read categories include

Cozy Mysteries. The modern Cozy Mystery is often (but not always) set in a small town or village, and involves a murder performed off-stage (with as little blood and gore as possible) that is solved by an amateur sleuth who is perceptive, intelligent, and unable to keep her nose out of police business. She often spends her non-sleuthing time engaged in some sort of craft, such as knitting or pottery-making, though a crafting hobby or career is not an absolute requirement. She does not swear (this is an absolute requirement), and if she has sex at all, we certainly never hear about it. For typical examples of the cozy, think Murder She Wrote, and Agatha Christie’s Miss Marple Stories.

Hard-boiled Mysteries. At the opposite end of the spectrum from the Cozy Mystery is the Hard-boiled Detective Story, which usually features a tough, street-smart private eye or detective with a lonely life and a somewhat questionable code of ethics. Well-known historical examples include The Maltese Falcon, by Dashiell Hammett, and The Big Sleep, by Raymond Chandler. A more modern example is Sue Grafton’s Kinsey Millhone Series, starring a female version of the hard-boiled detective.

Police Procedurals. The Police Procedural features the investigation and solving of a crime by police, and provides a realistic portrayal of police methods and techniques used in the course of an investigation. Think CSI: Crime Scene Investigation, or The New Centurians, by Joseph Wambaugh.

Suspense Novels. Suspense novels focus not on the solving of a crime, but on the anticipation that one will be committed. In the Cozy Mystery, Hard-boiled Mystery, and Police Procedural, we follow a sleuth as he or she uncovers clues to identify a murderer. In a Suspense story, we often know what will happen, and even who will commit a crime or murder. But we don’t know when the crime will occur or how it will be committed, and we are held in suspense as we watch the disturbing events unfold. Well-known suspense novels include Daphne du Maurier’s Rebecca, and nearly anything by Ruth Rendell.

Young Adult Mysteries. Young Adult (YA) Mysteries are written for teenage audiences, and generally feature teenage sleuths. Though YA mysteries resemble adult mysteries in most respects, the circumstances surrounding the crimes are typical of those experienced by young adults. The Nancy Drew and Hardy Boys Mysteries are among the best-known historical examples.  A more modern take on the category can be found in the popular Heist Society, by Ally Carter, and The Westing Game, by Ellen Raskin.

Mystery Non-fiction.
Mystery Non-fiction includes non-fiction related to mystery writers, and to the mystery-writing craft. Don’t Murder Your Mystery, by Chris Roerden, and Dorothy L. Sayers: The Centenary Celebration, by Alzina Stone Dale, are representative illustrations.