BOOK REVIEW : Heated Discussions With Arson Police : HEAT: The Fire Investigators and Their War on Arson and Murder <i> by Peter A. Micheels</i> , St. Martin’s $19.95, 240 pages

“A fire triangle,” as we learn in “Heat” by Peter A. Micheels, consists of the three classic elements of combustion: heat, fuel and oxygen.

But Micheels also teaches us about the other, equally explosive elements of urban conflagration: sexual perversion, racial and class hatred, the lust for revenge and sheer greed.

“Next to war, arson is humanity’s costliest act of violence,” Micheels writes. “Fires are started for revenge, for profit, for kicks, for recognition, out of fear or to cover other crimes. Arsonists . . . range from kids to little old ladies, from jilted lovers to Mafia wise guys, from teen-age crack dealers to lawyers and respectable businessmen.”

All these malefactors and their sometimes deadly handiwork come under the jurisdiction of the New York City Bureau of Fire Investigation--”the largest and busiest in the world,” according to Micheels.

In “Heat,” the investigators tell their own stories in a series of extended monologues that amount to a first-person encyclopedia of arson in the big city.

Micheels is a psychologist at Bellevue Hospital and the self-appointed chronicler of firefighting in New York. (His earlier book, “Braving the Flames,” is an oral history of the New York City Fire Department.) Each of the eight principle chapters in “Heat” is narrated in the voice of a veteran reminiscing about his experiences.

The fire cops initiate us into the arcana of arson detection: the landlord fire, the revenge fire, the arson-for-profit fire. They reveal how to distinguish between fires started by male and female pyros. They tell us why a professional arsonist uses kerosene, never gasoline, and why the color of smoke matters in an arson investigation.

One marshal explains why the position of a charred corpse on a bed is a clue to whether the victim died before or during the fire.

“Heat” is thick with the hard-boiled argot of the firehouse and the fire line--”The probie drove the Halligan in with the back of a long-handled ax”--sent me scurrying to the glossary that Micheels has thoughtfully provided.

Not even the glossary, however, is enough to help us fully decipher some of the highly charged jargon of the fire investigators--one man uses the term mutt interchangeably for dogs and people, but we are left to guess exactly what particular slurs are intended when the term is applied to “the mutts that were killing my friends and killing kids and adults in the South Bronx.”

Indeed, the subtext of “Heat” is the incendiary rage of the fire marshals for the miscellaneous bad people who are their prey--not only the professional arsonist but the slumlord who hires him to burn a tenement for the insurance money, the district attorney who bungles the case against him, the judge who sets him free though lives have been lost.

There’s no lack of color and character in “Heat,” plenty of action and suspense, even a few moments of humor and firehouse slapstick. At its best moments, it’s a dispatch from the trenches of a class war in which fire becomes a weapon of terror and vengeance. If there’s a weakness here, however, it’s the lack of a story--or, to be more precise, the vast overabundance of stories.

As I read the war stories and horror stories and inspirational stories scattered through the oral histories, I imagined that “Heat” will end up in the hands of some enterprising novelist who will use the richly atmospheric settings, the hard-edged street smarts and the agonized characters to create a thriller from what is now mostly raw material. Perhaps, and fittingly, it will be Micheels himself.

Next: Christopher Goodrich reviews “Something Leather” by Alasdair Gray (Random House).