In last week’s column, at the outset of my campaign to define and explain the various subgenres of mystery fiction, I explored the traditional mystery, commonly referred to as the cozy, which is the purest of all detective stories in terms of solving a puzzle.

In terms of solving a crime, however, a more realistic approach is offered by stories in which the police are the dominant figures. Let’s face it: When a murder occurs in real life, you’d probably prefer the police to come on the scene than a local vicar, personal trainer, or bookseller.

There are really two types of cop novels, and it’s difficult to separate them. In the first, a policeman is called in to solve a crime and sets about doing it. He acts alone and, apart from his training and official position, functions pretty much the way an amateur sleuth or a private investigator would.

Much later in the development of the cop novel the police procedural was created, in which an entire squad cooperates to find the killer. There are uniformed cops, detectives, medical examiners, forensic experts, psychologists, sketch artists, and so on. Of all crime fiction, these are the closest to the real deal.

STRUCTURE In both the cop novel and the police procedural, a crime (usually murder) is committed and the police are called. In the former the killer is hunted by a lone cop or, more frequently in modern stories, with a partner. The investigation is seen through his eyes, and while he relies on other people in the station house or precinct for help, it is generally his insights and doggedness that unravel the mystery.

Loners abound. So do rogue cops who have little difficulty breaking the law to nail the perp. They are frequently in trouble with their superiors and often the target of a psychopath who thinks he’s a criminal mastermind. They also have difficulty with the FBI, the D.A., journalists, and their wives.

The police procedural is more of an ensemble piece. Although inevitably certain characters are more interesting or intelligent than others, putting the bad guys away is a team effort. The methodology of detection is based on real-life police work, the crimes are thrust upon them rather than selected by free choice, and they frequently become involved with several cases at the same time.

HOW TO TELL If you are looking at a book with a badge on the cover, you can rest assured it’s a police novel. Other cliches include a police car, especially if its flashing red lights are in evidence. Titles may include a specific precinct or a bit of police terminology, such as “Code 6.”

THE BEGINNING The first novels using policemen in very prominent roles happened to be by two of the greatest writers of the 19th century, Charles Dickens (with Inspector Bucket in “Bleak House”) and Wilkie Collins (with Sergeant Cuff in “The Moonstone”). In France, Emile Gaboriau’s M. Lecoq was immensely popular.

It was in the memoirs of Francois Vidocq, a former criminal who created the first organized police force, the Surete, that investigative techniques were first described in 1828. But as time passed, police in the mystery genre were generally offered up as incompetent nincompoops while amateur detectives and private eyes took center stage.

The police procedural is generally regarded as having been created by Lawrence Treat in 1946 with “V as in Victim.” The author wrote eight more procedurals, but they never achieved major success. Hillary Waugh found some, with his 1952 novel, “Last Seen Wearing.” But it was Evan Hunter, writing as Ed McBain, who really put the procedural on the map. The first novel in the 87th Precinct series, “Cop Hater,” was published in 1956, and he is still writing with the same vigor and creativity a half-century later. His “Fiddlers,” due in September, has already received rave advance reviews.

THE GREATS Dickens, Collins, Gaboriau, Georges Simenon (creator of the wonderful Parisian detective, Maigret), Ngaio Marsh (creator Roderick Alleyn), Colin Dexter (and his beloved Inspector Morse) lead the parade of non-American police writers. The best of the British procedural writers may well have been J.J. Marric, whose Inspector Gideon adventures quickly became classics. Others include Bill Knox, Maurice Proctor, and James McClure, whose South African duo of Tromp Kramer (a white man) and Micky Zondi (a black man) had a lamentably short career.

Of Americans, the most distinguished cop writers include Dorothy Uhnak; Lillian O’Donnell; Dell Shannon; K.C. Constantine; William J. Caunitz; the ex-deputy police commissioner in New York, Robert Daley; and, in a different milieu, Tony Hillerman and his Navajo cops.

TODAY’S BEST In England, Ian Rankin (creator of John Rebus), Reginald Hill (creator of Dalziel and Pascoe), P.D. James (creator of Adam Dalgleish and Cordelia Gray), Bill James (creator of Colin Harpur), and John Harvey (creator of Charlie Resnick) write some of the most distinguished fiction written in any genre. None, though, is a purely procedural writer. The closest is Peter Robinson, now living in Canada, whose Alan Banks series is outstanding.

American police writers must pay obeisance to Joseph Wambaugh, who showed what it was really like to spend your life in a uniform. James Ellroy credits the former cop with giving him direction, and there can be little doubt Wambaugh also influenced such superstars as Michael Connelly (whose Harry Bosch is in the pantheon of all-time great detectives), John Sanford (whose Lucas Davenport regularly and deservedly makes the best-seller list), and James Patterson (whose Alex Cross series are among the best-selling books of all time).

Attempting to put any procedural writer in the same league as Ed McBain, however, is akin to finding a playwright who should be mentioned in the same breath as Shakespeare.

Next week: The crime novel.

Mr. Penzler is the proprietor of the Mysterious Bookshop. He can be reached at openzler@nysun.com.