HE GOT HUNGRY AND FORGOT HIS MANNERS By Jimmy Breslin Ticknor and Fields. 275 pp. $17.95

HERE IN New York, on 57th Street, there's a new skyscraper, an icy and imposing sheet of sheer glass that towers over the Russian Tea Room and Carnegie Hall beside it. In Jimmy Breslin's new novel, there's a party in progress there, in an apartment on a high floor.

Bushwick Taylor, a dedicated but very weary social worker who tries to keep hungry people from starving to death by supplying emergency food, has -- incongruously -- been invited to a party for some very sleek and fat cats who contribute money to such projects in the interest of salving their generally unruffled consciences. Bushwick and one of the fat cats are looking out the window at a winter nighttime view that includes the brightly-lit skating rink in Central Park. It's a pretty picture.

"Maybe we'll force people to skate all night," Bushwick says.

"Well, I don't see how you can make them," the man replies.

Bushwick suggests using convicts.

"Do you really think you could do that?" the man wonders. "Wouldn't the security be too costly?"

"Not if you locked the skates on their feet," Bushwick says. "Then they couldn't go anyplace."

"Wouldn't that be amazing?" the man muses.

And then Breslin himself observes: "His mind was at midposition between ludicrousness and actuality and for the moment he had no idea of which was correct."

That is also a fair description of He Got Hungry and Forgot His Manners, a novel poised, if ever a novel was, at midposition between ludicrousness and actuality.

Breslin is a tough writer. He shoots from the hip, his gun is loaded with rusty scraps of street knowledge, he acts out of conviction and his aim is pretty good. This time his subject is the attitudes of those who deal, or don't deal, with the poor and homeless: the society ladies who raise money but who also raise their elegant skirts as they slip past the homeless on the street; the people who guard the welfare computers that do or don't issue checks; all the bureaucracy that thrives on the poor.

A plot summary is out of the question. There's an Irish priest named D'Arcy Cosgrove who just got himself transferred from the African missions to New York; "bristling with celibacy," he is here to destroy illicit sex in America. There's his cannibal buddy, Great Big; substitute, if you follow wrestling, Kamala, the Giant from Uganda, and you'll have the picture. Cosgrove and Great Big land in New York and are instantly tangled up with a variety of black street toughs, the homeless and the poor, big city cops, the Mafia, monstrous urban bureaucracy, crumbling neighborhoods, selfish clerics, and a murder or two. Not to mention what Great Big does -- remember the title -- to his cellmate during a brief stay in the slammer.

NOBODY ESCAPES Breslin's potshots. Not the Church: "Race was silly for American Catholics to worry about because few blacks were Catholic." Not the Irish: "The Irish love to save distant blacks. Blacks in person are something else." And certainly not the rich: "The Poor are the most important people in New York, for their social welfare billions blow through the air for all the well-off to grab; where are the rich supposed to get their money from, the rich?"

There's much of that wisecracking tone here. And there's much of New York's proverbial color and variety; Breslin knows where those strange buses are going when they load up at night in Columbus Circle, for example, and he's seen the guy who plays an upright piano on the street, on Broadway at 61st. On the other hand, he has a tin ear for black English and not a clue about spelling Spanish. And then he wants to paint portraits of Mafia gangsters and New York cabbies, dissect the Howard Beach incident, and lecture us on our misdeeds, sputtering with conviction all the while.

There are dazzling scenes in this book -- wait till you see the firemen climbing that rescue ladder! -- and hilarious ones and upsetting ones, but in the end Breslin's conviction undoes him. Conviction, sincerity and rightmindedness are not substitutes for the discipline of writing. Breslin got so excited about his subject that he passed up neater and truer weapons, grabbed a shotgun, and just started blasting away. Much of the book is very actual -- very nasty and dead on target -- but much of it, too, is just plain ludicrous.

Alan Ryan is a novelist, journalist and travel writer. His latest book is "The Bones Wizard," a collection of short stories.