Mark Baker loves old war stories. In his first book, "Nam: The Vietnam War in the Words of the Men and Women Who Fought There," the battlefield was Southeast Asia, and Baker created a forum for the first-person tales of those who both faced and administered death there.

Now, in "Cops: Their Lives in Their Own Words," the methodology is the same, but the battleground has shifted to the streets, alleys and dingy tenements of urban America.

"Cops" is an oral portrait of the lives and -- in a few cases -- the deaths of police officers. Baker roamed the country persuading hundreds of men and women in blue to reminisce, reflect and confess into his tape recorder.

Many of the police who describe their experiences are not by nature introspective, but their straightforward retelling of what must surely be time-honed stories sheds light on an overglamorized and underanalyzed profession. What emerges is a picture of ordinary people trying to cope with an extraordinary job. The police are for some symbols of hope and safety, for others hatred and fear, for still others sexual fascination -- which from what they say is often acted upon. How the rank and file of the force handle the challenges and the disillusionments of their profession is the essence of these revealing memoirs.

By turns the material can be laceratingly funny or horrifyingly tragic. Cops find themselves under siege, either by demented madmen with guns and rifles, or, in one hilarious moment, by a lactating gypsy woman. Babies die in their arms, they stand by helpless while citizens kill each other over parking spaces, they perform heroic acts of crime prevention only to be slapped with morale-destroying lawsuits by victims and criminals alike.

Cynicism creeps into many of the reflections. Despairs one policeman:

"Whatever sacred cows you may have been feeding all those years are usually slaughtered after a very little while. That's probably the greatest single tragedy that every cop faces. You find out that nothing is on the level. You find out that people die for nothing.

"Whatever it is that drives people to religion is what you experience. And yet you're in a position where you can't accept religion, because you can't function that way. The job runs against every good impulse you ever had."

Police brutality and corruption are casually accepted, constitutional guarantees trampled, slovenly police work covered up -- all are revealed with surprising candor. Some cops are amusingly bad, such as the one who habitually ate the operator's license of anyone who dared to get surly at a traffic violation stop and then ticketed the person for driving without a license. Some are criminally bad, savagely abusing those arrested until the unwritten code against ratting against a fellow cop must be breached.

Fortunately, not every officer who gives testament to Baker suffers either from cynicism or corruption; most are decent, hard-working public servants perplexed by a society they serve that rejects them as often as it reveres them and a system of justice that offends their basic instincts about what's right.

Baker's strategy is ultimately the book's chief flaw. He lets his subjects speak without comments, and save for the expendable introductions to each chapter, we hear little of the author. The result is too much anecdote, too little perspective; one's patience is tried by being always the vicarious listener, just as any outsider eventually tires of a night of relentless shop talk.

Such bull sessions can be found in Washington easily enough; just sit in any lounge of D.C. Superior Court with police officers waiting to testify or at any station house at the end of a shift. Every cop has his stories -- just as every prosecutor, every defense attorney and probably every defendant has his. Whereas any one career of 20 years might produce four or five worthy anecdotes, "Cops" is a distillation of the careers of more than a hundred police officers; most are top-drawer tales, tales rivaling the imagination of a Joseph Wambaugh or the writers of "Hill Street Blues." The author's problem is that, despite thin attempts at grouping the anecdotes by subject, the cumulative result lacks any satisfying pattern and coherence. But, then, that's what the police found about the streets.