For nearly one-third of "The Pope of Greenwich Village," the reader can relax with the pleasant illusion that the author is trying to be a new Damon Runyon. There is a colorful, slangy, "Guys and Dolls" quality in the central characters, Charlie Moran and his cousin Paulie, that promises a few quick laughs at the expense of the New York underworld. Their problems are essentially comic problems -- matters of style and status, the challenge of hustling a dollar or a date, dreams of hitting the number and getting free of pawnbrokers and loan sharks.

Then something happens, the plans of these petty criminals begin to fall apart, and suddenly Vincent Patrick is functioning not in the fantasy world of Runyon but in the more gritty reality encountered in the novels of Joseph Wambaugh or George V. Higgins.

What happens is that someone dies (a policeman, almost by accident) in the middle of a small-time burglary, and suddenly Charlie and Paulie are no longer on the outer fringes of the underworld but right in the middle -- in deep trouble with both the police and "Bedbug" Eddie Grant (alias Grantullo), a leader of organized crime in lower Manhattan.

Patrick has done something very tricky -- particularly for a first novel. He has taken a collection of stereotypes and caricatures, and he has slowly transformed them into real people.

They are an unlikely crew for such an operation: corrupt policemen taking bribes routinely from organized crime (which seems rather disorganized by the end of the book), and petty criminals who scrape along on small swindles while they wait for some heavy action to make then rich and respected. s

Except for Bedbug Eddie, who likes to cut people into pieces and mail parts of them to their families and friends, the characters hardly seem terrible enough even to be interesting monsters. But they all have their special problems, their more or less noble instincts and aspirations, and Patrick's triumph is that he manages to make the reader care about what happens to them -- even Bedbug Eddie.

The mainspring is Paulie -- though Charlie and a safecracker named Barney are ultimately more sympathetic characters. In Paulie's world (he is waiter in a Greenwich Village restaurant where Charlie is the night manager), a man's worth is measured by the car he drives, the roll of bills he can flash in public places, the size of the tips he leaves to impress the women he will later abuse.

Paulie has been known to tip even a tollbooth attendant in his scramble for status, but it doesn't help -- he is still a nobody who makes most of his income chiseling the restaurant's absentee owner, hounded by loan sharks and dreaming wild dreams of wealth and power. Finally, he buys a part interest in a racehorse (a "turrow bed," as he calls it, though this horse is a thoroughbred only by hearsay), and finds that his new plaything is only getting him deeper in debt.

When he finally persuades Charlie and Barney to join him in a burglary, it is a total disaster. It turns out that the trucking company they burglarized belongs to Bedbug Eddie, and the money they've stolen is Eddie's regular payoffs to New York's Finest, who are understandably disturbed.

Patrick handles his abundant plot with neat complications and occasional surprises -- but it is not the book's main attraction. More important ingredients are the dialogue -- almost as tight and phonographic as early Higgins -- and the picture of an alien world, an almost totally corrupt society, in which the people are still recognizably members of our own species. s

Novels in the "Godfather" vein are hardly a novelty any more, but Vincent Patrick has managed to produce one that rings true most of the time and stays interesting from beginning to end. When Bedbug Eddie tells Charlie "I got to keep everybody's respect . . . If i can't get their respect out of love, then I'm forced to get it out of fear," Patrick manages to make it sound brand new. A small triumph, perhaps, but a real one.