The rules for police procedural mystery novels, unfortunately, are very strict, allowing for almost no license on the part of the author; so, the following may strike readers as somewhat cold-hearted or even poetically stingy. Tough!

A Law Enforcement Manual

1. The protagonists are cops.

2. The cover art of procedurals always features a "unit," customarily rendered in blue and white, with a bubble gum machine and flashing lights on top. The backdrop is a cityscape. At night. You can see your own grubby fingerprints plainly on the shiny cover and realize it's too late to return the book to the shelf. You sheepishly buy it and slink out of the store.

3. The jacket of the procedural must include one blurb that fairly shouts "FRESH AS TODAY'S HEADLINES."

4. The word "unit" has no sexual or anatomical connotation in these novels, as in "calling all units, we need backup on Astoria Boulevard."

5. The squad room must be populated by what is known as the "Rainbow Shift" or "Doppler's Revenge." The cops ideally will represent every ethnic group under the sun. To omit even one minority is to break the rules of the procedural, and you will find that you have produced a book that does not fit this category and may be eligible for a National Book Award.

6. The cops do not mind that the crooks are all wealthy, even though the goods are ill-gotten. Cops don't care about tainted money because they have something even better: Mastercards.

7. The cops in procedurals do not use their units, as sex is not allowed in this subgenre. At least, not good sex.

8. Despite rule #6, at least one cop must be corrupt, accepting bribes, or sifting through evidence bags for a roach or two, or moonlighting as a schools superintendent.

9. The cops drink to excess: the results are precocious paunches and the kind of hangovers historically only produced by Cecil B. DeMille. You'd drink, too, if you had only two years to go until retirement and the new Republican mayor is balancing the municipal budget through cutbacks on the force.

10. Procedurals take place in big cities because small towns lack criminals worse than aluminum siding salesmen.

11. Readers of procedurals have the right to remain silent.

12. Reviewers of procedurals have the right to representation by a public defender who was once a hotshot courtroom lawyer but who is now making his way slowly back into the legal field after a bout with alcoholism or repeated sexual misconduct with the jury pool. These losers, who must wear threadbare brown suits, almost never win their cases. That last sentence fails to make it clear if the "losers" are the public defenders or the reviewers.

13. It is essential that the crime be a big one. A single murder or DUI is beneath the squad room's attention and is handled by "uniforms." The big crime typically involves the "syndicate," or labor racketeering, or narcotics, or loan sharking, or extortion, or point shaving in the NBA, or following a fire apparatus too closely. In other words — anything that will cause Internal Affairs to stock extra Tums. The hideous irony is that the sub-plot being worked by the lowlife uniforms always provides the key to the final solution of the big crime.

14. Before the hideous irony is revealed, the cops attempt to solve the crime through the use of procedures: wiretapping, cross-dressing, the chain of evidence, off track betting, MO's, makes, police brutality, stool pigeons, disobeying one's commanding officer, rap sheets, sirens, eating doughnuts, talking about the "perp," marrying the Don's sister, and driving a Ford Crown Victoria with radiator problems.

15. The language of procedurals is impossible to understand if the reader has not graduated from a decent police academy. Often, numerals do the work of words, as in "86," "Ten-Four," "That's a .357 Magnum," "I'm calling from a pay phone outside a 7-11," and "Unit 41 to dispatcher — we're going on a 10-91A." (I looked it up, and a 10-91A is a "noisy animal complaint.")

16. Finally, readers do not take these books seriously if the books appear to have been written by a woman. Therefore, women wishing to write procedurals adopt the practice of using their initials instead of their given names, especially if those initials are particularly masculine. (I can only think of one set of really masculine initials, and that's Y.A.)

Submitted by Polly Whitney, who has read exactly two police procedurals in her life.