Kurt Vonnegut surveyed the crowd and concluded, "There is no literary establishment in this country. But if there were one, this would be it."

A healthy contingent of some of the most impressive figures on the New York literary scene had crossed the East River Monday night to celebrate at an elegant waterfront cafe in Brooklyn the publication of William Styron's long awaited novel, "Sophie's Choice" and his 54th birthday.

But they came out of their affection for the man more than for the event, and the evening glowed with a warmth that transcended the usual brittleness of such literary affairs. Bill Styron and his family were among friends.

Random House spent some $15,000 on the party to promote the book, much of which takes place in Brooklyn, and to tell Styron that it really doesn't mind that it took him a decade to write it.

"Every summer, an army of editors from Random House came up to Martha's Vineyard to see how he was doing on his book," Art Buchwald wrote in his letter of regret, which was read to the crowd of 200 by Random House president Robert Bernstein. "They always went away depressed. Today, they must be very happy."

So was Styron. The paperback rights to the book, soon to be a Book-of-the-Month-Club selection, were sold to Bantam Books a few days ago for over $1 million.The movie right went for $650,000, and director Alan Pakula was at the River Cafe Monday night as the man who will bring the story to the screen. Filming, he said, should begin next summer in this country and in Europe.

Elizbieta Chezevska, former wife of David Halberstam, is actively seeking the role of Sophie, a Polish survivor of Auschwitz. "How many Polish actresses do you have over here?" she asked.

Many faces went back a long way, George Plimpton, Peter Matthiessen and his former wife, Patsy Southgate, and Tom Guinzburg all first met Styron in Paris in 1953, in the heady days when they collaborated on the then fledgling Paris Review.

"Bill wrote the introduction to our first issue," Plimpton recalled. "He was a star writer in Paris then. His book, Lay Down in Darkness,' had won the Prix de Rome and was extremely successful in Paris."

Glorai Jones, widow of James Jones, has been close to the Styron family since 1952, when the first met in Greenwich Village. The two families have seen a good ideal of each other over the years, even though they were often an ocean apart.

"Bill and Rose and the kids would come over when we were living in Paris, we'd all take off together," she said. "I remember one year we all went to Biarritz and had a marvelous time."

Elizabeth Hardwick, Francine du Plessix Gray, and John Marquand, all of whom have known the Styrons for years, were there Monday, as were Vonnegut and Jill Krementz. Tom Wicker and Pam Hill, Harrison Salisbury, Gail Sheehy, Arthur Schlesinger and his wife, Stephen and Jean Kennedy Smith, and Elaine Kaufman, the celebrated Manhattan restaurateur.

Then, too, there was the striking face of Richard Wildmark, who is not exactly a regular on the publishing circuit. "I've been a neighbor of Bill and Rose for years in Roxbury, Conn.," Widmark said between bites of steak tartare. "I'm just here to help them celebrate."

Styron basked in the glow of the evening, usually with a scotch and soda in hand. He had every right to. He had assembled at his publisher's expense many of his close friends for a great party. Random House may have added some literary critics and other figures to the guest list, but the evening belonged to the family Styron.

All six of them were on hand to greet many of the guests who arrived in two buses rented by Random House. The arrivals moved quickly into a roomful of sumptuous hors d'oeuvres and drinks before sitting down to dinner and later dancing with a spectacular view of Manhattan and the Brooklyn Bridge.

"When Delacorte threw me a party a few years ago, they only served peanuts," Vonnegut grumbled as he headed for the smoke trout.

Robert Bernstein spoke warmly of Styron before turning the microphone over to him as wine glasses were being refilled after the meal. Styron then managed somehow to thank a host of people without making his remarks sound like an acceptance speech at the Oscars.

"You have helped me validate the idea that the novel is not dead," he said. "I may be the only writer alive with a passionate love affair with a publishing house."

Styron acknowledged a debt to the late Bennett Cerf, who, he said, would have had "enormous, chuckling pleasure to be here tonight."

But he saved his deepest gratitude for his editor and his famly. Robert Loomis, a classmate at Duke and the man who helped pay for the rented room in Brooklyn that later became the seed for "Sophie's Choice," performed "incredible legerdemain" in the editing process. "He's the man who this thing together," Styron said.

He thanked his children for "putting up with a lot of crap over the years" and his "long suffering" wife, Rose, whose name drew thunderous applause from the audience. Finally, he paid tribute to "an unspoken figment of my imagination - Sophie."

Later, a giant birthday cake with a remarkable likeness to the dust jacket of the "Sophie's Choice" was brought to Styron's table. The half of the cake that represented the back cover of the book, which includes a large picture of Styron, was preserved and disappeared under a layer of aluminium foil.

Styron and his wife returned to Manhattan with the last Random House bus. They'd had a hell of a time, and there was only one television appearance he had to make separating them from another season on Martha's Vineyard. CAPTION: Picture, William Styron (with cigar) and his wife, Rose, left; by Donald F. Holway for The Washington Post