A FAIRY TALE of New York is a risky title for a book. It's risky because so many other fairy tales have been written about New York--about people who go there to put flesh on their hopes or to work out their frustrations. But, largely because of its freshness and style, J.P. Donleavy's new book manages to outlast most of its competition.

Donleavy's central character is Cornelius Christian, born in Brooklyn, reared in the Bronx, and returned from the continent, sporting cultured manners and accent. With good looks, and erratic opportunism, Christian is the type of figure that the image of cold, yet capricious New York is built around. He communicates by shock. Flattering several matrons in an elevator by immediately identifying them as members of the Daughters of the American Revolution, Christian informs them that one of them has certainly stepped in dog excrement. In the park, he systematically picks out obese women to ask them if they want to fornicate.

This is what suceeds in the big city, at least for a time, according to Donleavy. Fresh off the boat from the continent, his wife having died on the voyage, Christian lands a job with the mortician who buries her. The mortician is impressed by Christian's good looks. On one of his first assignments for the funeral parlor, Christian is willingly seduced by Fanny Sourpuss, the young widow of an old multimillionaire garment manufacturer. Sued by the widow of a rich corpse that Christian has butchered in the embalming, he wins the suit by charming judge and jury. Women, including cafeteria acquaintances and wives of coworkers, fall at his feet. Christian is the parody of the fairy tale hero, lusting after fallen princesses in honky-tonk New York.

What makes Fairy Tale a successful book is Donleavy's ability to subtly exploit the cruelty and humor contained in the gap between Christian's appearance and reality. Set in New York, the style that gives the fairy tale hero instant acceptance is the same one that turns Christian into a man who is both exploiter and exploited. It is his style which wins him jobs and pushes him into brawls and disastrous affairs.

Donleavy wrings sentiment slowly out of his hero, often tempering nostalgic images of the city with cruel childhood memories. He is particularly effective in dealing with the funeral of one of Christian's friends, and in the following passage, which is set inside the hearse at the funeral of Christian's wife:

Where I waited with Helen we wait for green on the stop lights. In my own romatic Bronx. I was a new little boy all the way from Brooklyn moved on the street. Made a friend called Billy whose mother just died. He asked me over. To try out his boxing gloves he got for Christmas. His father watched us from a ring side seat on the cellar stairs. I thought he would be too sad to fight and instead he beat the living shit out of me.

Donleavy's greatest asset is his own clipped, ungrammatical style, which reads quickly and cleanly, giving maximum impact to shocking references. But his heavy reliance on vulgar images weakens their shock value, as in this discription of a Queens neighborhood.

Walk east crosstown. Wind biting and raising whorls of grit and paper scraps. See the sky blown blue somewhere far out over Flushing. As a little boy I thought it was some strange big toilet bowl, Where giants took their craps.

DONLEAVY IS MORE successful in populating the big city with a host of tortured and combatative New Yorkers. He prods his hero with encounters with nervous executives, diffident bums, desperate women, fat Mafia men, and seemingly ubiquitous subway perverts.

But his clearest image of New York is that of a city of struggle and death. Christian finds murder going on all around him, and a constant challenge to become involved in the sea of fighting. Barroom brawls lead to murders as he watches. He and his mistress, Fanny, spy on a murderess who goes through a husband and a lover before the police catch up with her. And, once he becomes attached to her, Fanny also dies. Finally convinced that he will certainly die if he stays any longer, Christian leaves the city, heading back across the ocean.

Beneath its florid style, Donleavy's fairy tale of New York is stark and compelling. Parts of A Fairy Tale of New York appeared as a play, "Fairy Tales of New York," which was produced on the London stage in 1961. In the novel, an enlarged and fundamentally altered work built around the play, Donleavy has stripped the classic fairy tale of its sharp dichotomy between good and bad, while retaining many of its mythic qualities. He has written an intensely personal vision of universal gloom. Like his hero, Donleavy was raised in New York, and like him, he sports a cultured accent, acquired at Trinity College in Dublin, and through life in England and Ireland.

The cab driver who drops Christian off at the pier to take a boat out of New York tells him there are only two kinds of people in the world: "Guys who'll stand around being nobody for an hour so they can be somebody for a minute and maybe bore ten years' patience out of a big shot's life who don't want to listen. But then you get the other kind. The Acquaintances. Who really want to let you know they're close friends by drinking all your drink and eating your food. So I ask sincerely, who needs them."

In the end, this is a vision which may prove unsatisfactory. Fairy Tale is a book of vignettes and strings of first impressions, and therefore Christian sits uneasily as a symbol of New York, and the work is not equipped to cover the sweep of a great city. For such broad subjects, Fairy Tale is a narrow perspective, but like its hero and his hometown, it gains a hearing by being brash and bizarre.