Si Newhouse understands that he is to be seen and not heard.

No matter that he is worth $700 million plus and, with his brother, owns the biggest privately held media empire in the nation. This patron of the arts and mover in New York's literary world (and occasional guest at the White House) has also bought The Magazine.

The Magazine is, of course, that idiosyncratic temple of urbanity: The New Yorker. Its purchase by the 57-year-old publishing magnate, to be ratified by stockholders today, has sent tremors through the city's literati and brought trauma to the ranks of the magazine's distinguished writers.

Recently, a defiant "Talk of the Town" piece by the magazine's legendary and reclusive 77-year-old editor William Shawn put Samuel Irving Newhouse Jr. in his place. "We reassert our editorial independence," wrote Shawn, adding that in the past 60 years, neither the first owner, Raoul Fleischmann, nor his son Peter, who succeeded him, "ever made an editorial suggestion, ever commented favorably or unfavorably on anything we published or on any editorial direction that magazine was taking, ever permitted the advertising or circulation or accounting people to bring any pressure to bear on us."

Shawn, who had earlier hired a lawyer when he'd heard of the impending sale, and nearly wept while telling his staff about it, was now, in a tone of high moral fervor, telling the world that it didn't make any difference. "The business ownership of The New Yorker may change hands, but the idea of The New Yorker -- the tradition of The New Yorker, the spirit of The New Yorker -- has never been owned by anyone and never will be owned by anyone. It cannot be bought or sold. It exists in the minds of a group of writers, artists, editors and editorial assistants who have been drawn together by literary, journalistic, aesthetic and ethical principles they share . . ."

So is Si Newhouse angry? Offended? Hurt? Surprised? Sorry that he spent $168 million only to be so rebuffed? Not a bit.

"It was very elegantly put," he says, in a tone of benign serenity. "It was a great opportunity to state for the first time the basic philosophy of the magazine. I thought it was terrific . . . It was quite refined and attractive. I couldn't have been more delighted with it."

On the 14th floor of the Conde Nast building on Madison Avenue, in an office as bland as an insurance agent's, the Media Mogul reveals himself as a mild-mannered man. The Mogul, who normally avoids the media like the White Rabbit eluded Alice, has granted this interview with extreme reluctance.

"I don't think there's much to talk about," he says at the outset.

Tieless, dressed in a striped shirt, a black sweater-vest, gray slacks and loafers, he has a casual, Middle American air. Hardly handsome, he charms with a bashful twinkle, a whiff of "Noo Yawk" in the accent and a refusal to act as if he owned a conglomerate valued at $1.5 to $2.7 billion.

(His childhood friend, lawyer Roy Cohn, introduced Newhouse to Secretary of State George P. Shultz at a recent function. "You know Si Newhouse, of Newhouse Newspapers," said Cohn, all smiles. "No," replied Shultz, looking blankly at the man whose publications reach 25 million readers. Cohn later marvels: "It's a phenomenon of American life that nobody knows who Si Newhouse is.")

While speculation over Newhouse's motives and plans is rife, the modest Mogul is intent on soothing all fears. He speaks of The New Yorker in reverent tones. "I have a good deal of faith in any publication that publishes with integrity, with quality, with imagination," he says. "The New Yorker has this extraordinary history. Its past can be its future."

As for the editor, the man his writers call Mr. Shawn even when they've known him 20 years, the cloistered, courtly father figure who once telephoned Kenneth Tynan in Havana to ask if the writer minded if he changed a comma, the shy septuagenarian who is hip enough to write John Lennon's obituary, the incarnate myth who dines on cornflakes and poundcake at his regular luncheon table at the Algonquin Hotel, who works at all hours of the night and, for 33 years, has read every word that goes into the magazine -- "the Druid" as a recent novel, describing a magazine loosely based on The New Yorker, dubbed him . . . why, Newhouse looks positively startled when asked about The Succession.

"Mr. Shawn is a very young 77," he says, choosing his words carefully. "I've had several meetings with him. I found him very vital intellectually and physically. I hope he continues to edit the magazine for a long, long time. Obviously Mr. Shawn will continue to be editor as long as he wants to continue to be editor. He is so much The New Yorker. To say he is there at my sufferance would be presumptuous. He's going to be there because he's Mr. Shawn. Just as I wouldn't change the name of the magazine, I wouldn't change Mr. Shawn."

Newhouse dismisses rumors that he will appoint Robert Gottlieb, president of Alfred A. Knopf, the Newhouse-owned publishing firm, or Robert Silvers, editor of The New York Review of Books, when Shawn decides to retire. "I think a successor will come out of The New Yorker itself," he says.

When S.I. Newhouse Sr., from Bayonne, N.J., son of an immigrant garment worker, died in 1979 at the age of 84, he left his two sons, Si and Donald, an empire judged to be the fifth biggest communications conglomerate in the nation, after ABC Inc., CBS Inc., Time Inc. and RCA Corp. Unlike those four, it has no nonfamily stockholders and no outstanding debts. The senior Newhouse's death left his sons battling the government in the largest estate tax case in history, with the IRS claiming $914 million in taxes and civil fraud penalties. Si and Donald are the 17th and 18th richest men in America, according to Forbes.

Donald runs the 29 newspapers, including dailies in Newark, St. Louis, New Orleans and Cleveland, and one of the nation's largest cable TV systems. Si runs Conde Nast, with its score of magazines, including Vogue, House & Garden, Glamour, Gourmet, GQ and Bride's. He has jazzed up the Sunday supplement Parade. And in 1980 he bought Random House, widely considered the nation's most important publisher, from RCA. To mixed reviews, he has revived Vanity Fair, the fashion and cultural magazine of the 1920s, with a distinctly 1980s glitz.

But nothing Si Newhouse has done since he dropped out of Syracuse University nearly 40 years ago to work in the family firm has caused such a stir as buying the magazine of James Thurber, Vladimir Nabokov, E.B. White, Dorothy Parker, John O'Hara, J.D. Salinger, John Cheever, Rachel Carson, John Updike, John McPhee et al.

On the afternoon the sale was announced last month, Shawn, a balding, slightly stooped figure with a whispery voice, addressed the staff from a stairwell landing in the magazine's decrepit 43rd Street offices. "The editorial staff was not a party to the negotiations," he reportedly said, pausing several times to regain his composure. "We were not asked for our approval, and we did not give our approval."

Some of those who listened cried, others reacted with anger. Paul Brodeur, a longtime staff writer, told a New York Times reporter staking out the meeting that the sale was "a deliberate affront to every artist, writer and editorial staff member." Emily Hahn, another writer, said she felt "like a slave went on the block." A dozen staffers formed an "editorial council" under Shawn to study the sale and talk to lawyers in an effort to guarantee the magazine's editorial independence.

"There was a good deal of anger that the staff had never been consulted in the deal," says James Lardner, a staff writer and grandson of Ring Lardner. "Perhaps that implied a certain naivete' or arrogance . . . but that's the way we felt."

In recent weeks, emotions have calmed. Shawn has met several times with Newhouse and said of his new boss, "I will try, as I do with anyone who comes here to work, to establish a relationship of mutual trust. I would hope that as man to man we could work things out." While one old-timer remarked that the statement, reported in The Times, made it sound as if Newhouse were coming to work for Shawn, rather than the other way around, Shawn nonetheless warned the new owner of his impending "Talk of the Town" piece, a small concession to communication between the worlds of art and commerce. Shawn has declined to be interviewed since the initial stories in March about the sale.

A few on the staff have spoken out in Newhouse's favor. "I'm considered Judas Iscariot around here," says drama critic Brendan Gill, resident historian by virtue of his 49-year tenure and his book "Here at The New Yorker." "But it strikes no terror in my heart to think we could become part of the Newhouse kingdom."

Gill, a social friend of the Newhouses, pooh-poohs his colleagues' anxieties. "If Christ risen had bought it, they would be saying, 'Where did he come from?' " he says. "We've always been a collection of individual eccentrics. It's a function of our character that all change represents the risk of catastrophe."

Still, Si Newhouse, while he may have a spectacular modern art collection in his Upper East Side town house -- he's a trustee at the Museum of Modern Art -- and while he may give elegant parties for Alison Lurie and Norman Mailer, is the son of a man whom The New Yorker's own A.J. Liebling called a "journalist chiffonier," a ragpicker of second-class newspapers. Old man Newhouse -- "The Union-Busting Duke of Staten Island," picketers called him outside his first paper, the Staten Island Advance -- fought the Newspaper Guild to a bloody standstill, forging a reputation for squeezing profits with brutal business tactics and little thought of editorial quality.

He was a man, Liebling wrote, with "no political ideas, just economic convictions."

Years later, a younger staffer at The New Yorker worries that Si Newhouse "may be a more civilized offspring, but maybe not civilized enough."

Gill scoffs at such talk. "People like the Newhouses are infinitely more sophisticated and much more intellectually and culturally oriented than 90 percent of the staff of The New Yorker," he says. "Si is an intellectual. He's not the head of a shoe conglomerate."

On the bulletin board in a scruffy hallway on The New Yorker's 20th floor, someone recently posted Vanity Fair's March cover: a photo of Jerry Hall, Mick Jagger's girlfriend, sprawled nude on a bed in Rio. On her face, the jokester had pasted the image of Eustace Tilly, The New Yorker's Edwardian dandy, as if to needle the new owner on the incongruity of his media merger.

Vanity Fair is Si Newhouse's creation, and many of the serious-minded denizens of The New Yorker take a dim view of it. Humor at The New Yorker -- apart from its legendary cartoons -- consists, for example, of a recent satire on the movie "Amadeus," taking off on the middle names of other famous composers -- Franz "Joseph" Haydn, Ludwig "van" Beethoven. As for sex and explicit language, well, we're talking about a magazine -- though somewhat more relaxed in recent years -- that once insisted on changing the word "pissoir" in a review of a French comedy to "circular curbside construction."

New Yorker staffers say their magazine is more "moral" than others. It banned cigarette ads, for instance, after the surgeon general's 1964 report. It gave over an entire issue to John Hersey's "Hiroshima" and published Rachel Carson's "Silent Spring" and, more recently, Jonathan Schell's "The Fate of the Earth" on nuclear war. Shawn's recent "Talk of the Town" resounded with the cadence of a religious credo: "In an age when television screens are too often bright with nothing, we value substance. Amid a chaos of images, we value coherence. We believe in the printed word. And we believe in clarity. And in immaculate syntax . . ."

Newhouse says he will keep The New Yorker separate from Conde Nast. "I wouldn't make Vanity Fair like The New Yorker and I wouldn't encourage The New Yorker to be like any other magazine," he says.

So did Newhouse have profits or prestige in mind when he bought the 60-year-old magazine, a less than stellar business property with its static circulation of some 500,000, declining ad pages and an aging, albeit fanatically loyal, readership?

"At this stage of my life, prestige is not anything I'm into," says the man who owns a house in Palm Beach but prefers to go off-season; who could afford 10 company planes, but always flies commercial; who gets in to the office at 4 a.m., works nine hours and goes to bed before the charity balls begin.

Newhouse's second wife Victoria owns a small architectural press and is writing a biography of the late architect Wallace K. Harrison. His three children by his first marriage are grown -- a son, 30, is in the computer business; a daughter, 28, lives in Paris; and a son, 33, is publisher of the family-owned Jersey Journal.

(At one point, 64 Newhouses were working in the company. "They were sweeping the floors," Si Newhouse laughs. Now it is a mere 14. The Newhouse empire is one of the few conglomerates with virtually no professional corporate managers.)

A New Yorker reader since Horace Mann high school, Newhouse says he had had no thought of buying it until an investment banker called last November to tell him that a 17 percent minority interest was available. "There's an expression attributed to Napoleon: First charge and then see what happens," he chuckles.

He later decided to buy a majority share "because I like The New Yorker. I like to publish. It's an enriching experience aside from the business objectives. I'd grown up in New York. In my life, I'm closely tied to what's happening in this city culturally, politically. The New Yorker, through its articles, its reviews, is the whole history of New York City. I've been growing up with The New Yorker all these years."

Roy Cohn, who was chief counsel for Sen. Joseph McCarthy, who has defended reputed Mafia chieftains and whose office contains six personally autographed photos of President Reagan (one of them inscribed "with deepest appreciation for your love and support"), is Newhouse's best friend. "I've never seen Si so excited about anything," Cohn says of Newhouse's purchase of The New Yorker. "There's an element of class to it which he respects. It's like the crown jewel."

He predicts that Newhouse, who, he says, has been full of ideas for his other properties -- sending Norman Mailer to Russia for Parade, trying to lasso Jeane Kirkpatrick's book for Random House -- will put his stamp on The New Yorker within a year or two. "But Si is the most subtle stamper I've ever met in my life," he says.

Cohn says Newhouse is "one of the most apolitical people I know," but, if pressed, says Newhouse would be "a conservative with a high tolerance for ultraliberals." Newhouse, on the other hand, describes himself as a registered independent with a strong interest in politics, adding that his ideology and Cohn's are far apart.

Nonetheless, when Cohn was three times tried -- and thrice acquitted -- on charges of fraud, blackmail and perjury in the last two decades, Newhouse came every afternoon to the courthouse as a gesture of friendship and loyalty.

"Si is very shy," Cohn says. "He's terrorized by public appearances. When he has to give a five-minute speech, he rehearses four to eight weeks. If I have a party he calls and his opening line is, 'Do I have to come?'

In 16 years, says Newhouse's secretary, Lillian Singer, "I've never once heard him raise his voice." Business associates say he's not one for small talk and makes decisions quickly. "The New Yorker is going to find him first-rate," says Robert L. Bernstein, chairman of Random House, who lunches with Newhouse once a week at the Four Seasons. "He's curious, he asks questions. But he doesn't interfere with the day-to-day management.

"He'll pick up on news stories about Halley's Comet and say, 'Shouldn't we have Carl Sagan do a book on comets?' He wants to be one of the people throwing suggestions into the pot, but he understands if they're turned down."

Tina Brown, editor of Vanity Fair, says Newhouse is "very discreet, low-key. He has a very sophisticated sense of humor. You get a sense he's really quite hip. He likes quality. House & Garden was making pots of money, but he didn't like it. He made it better. GQ was too gay. He changed it.

"The New Yorker should be so lucky as to be bought by Si Newhouse. They could have been bought by Rupert Murdoch!"

Clay Felker, the founder of New York magazine, says it is hard to find anyone who dislikes Newhouse because "people like working for Conde Nast. Si Newhouse is honorable, very intelligent, enlightened. I was amazed at the hoorah coming out of The New Yorker. He was the best person to buy it." Felker added that GQ publisher Steven Florio, who will reportedly take over the business side of The New Yorker, "is a hotshot who will bring aggressive sales and modern marketing to the selling" of the magazine.

There is, however, fear at the magazine that what Shawn has called its "peculiarities" of management may not survive. Not even the top editors claim to know how many staff writers there are. If there is an editorial budget, no one seems to have heard of it. Writers are not on salary, but are paid -- handsomely, by most accounts -- through individual understandings with Shawn. Writers have offices for years without writing a word. Editors never give writers assignments. Stories are published even decades after they're written. (A small piece on Henry James by John Updike may hold the record. It was submitted in January 1961 and ran on April 19, 1982.)

"No writer or artist or editor is ever given an order . . . " Shawn wrote in "Talk of the Town." "And no editing is ever imposed on a writer . . . And our editors edit only what they are willing to edit."

All this, says Newhouse, is fine with him. "I'm interested in The New Yorker on its own terms," he says. "It is unique in the world. It has developed as a certain form of publishing. To transform it into something it isn't -- for that, I don't have to buy The New Yorker. I can contribute to its future by maintaining a strong business support to this extraordinary editorial product.

"I don't think they need me to suggest that they should use one short-story writer versus another. They know much more about it than I do."

As for management practices, the magazine, he says, is "so intense, so refined, it could only come from this hothouse atmosphere in which so much focus is given to quality and so much respect for the written word . . . So much goes into each major piece, with so seamless a result -- the only way this could ever be achieved is by throwing away the rule books."

The mild-mannered mogul is allowing his picture to be taken in front of a wall-length rack of his magazines. He wonders, has the reporter spoken to many people at The New Yorker? The answer is yes, and the takeover is a frightening experience for some of them.

"It is for me, too," he says, laughing.