Shelley Winters was waiting for a table at Sardi's recently when a breathless trio of middle-aged women approached her with a question: "Which one was the best?" they wanted to know.

Which one, they meant, from among Burt Lancaster, Marlon Brandon, Errol Flynn, Vittorio Gassman, William Holden and Anthony Franciosa -- the principal celebrity lovers Winters has honored with mentions in "Shelley -- also known as Shirley," which has sexually assaulted the best-seller lists and climbed on top so fast it has the other books gasping for mercy.

What made Winters decide to go public with her love life? "Women never discuss this with me -- women reporters," she says indignantly. But then she settles back into the soft blue cushions of her living room couch, and meets the question head-on. "I'll tell you why I did it. Through centuries there has been this double standard. Men -- I mean what are locker rooms for? You know who Warren Beatty is sleeping with, don't you? And Burt Reynolds? . . . I think women should be as free as men are."

Or as reticent? "Or as reticent," she agrees. But her mind is on the photographer in her peripheral vision. She toys with a scarf that hangs around her neck, trying different effects. Then she realizes she has forgotten her eyelashes. "But maybe an author doesn't need eyelashes," she says. And she hasn't found the right posture for the camera. "I don't know how to sit as an author. As an actress, I knew how to sit."

When the train of thought gets back on track, she notes that Anna Kafshi, Elizabeth Ashley and Brooke Hayward all revealed more than she did, and Lauren Bacall was readier to pass judgment on the men in her life. "I was, if anything, showing good taste . . . I wanted to be careful that I wasn't getting even with anybody."

If Winters is not the first show-business figure to find sex worth writing about, her revelations have the allure of surprise. Who would have thought this 57-year-old portrayer of nagging housewives, insufferable mothers-in-law and other unwanted cargo would be the guardian of such a risque and star-studded past? Winters is your Aunt Mollie as Mata Hari.

Moviegoers with longer memories, however, remember a different Shelley Winters, young, beautiful and fragile, with an unfortunate habit of being murdered by her leading men -- Ronald Colman in "A Double Life" (1947), Montgomery Clift in "A Place in the Sun" ('51) and Robert Mitchum in "The Night of the Hunter" ('55). She put on weight to play the mother in "The Diary of Anne Frank" ('59), and that got to be a habit too. Finally in "Lolita" ('62), giving one of her most memorable performances, she made the transition to the bigger, brassier movie persona with whom, ever since -- and especially since "The Poseidon Adventure" in 1972 -- she has been inseparably identified.

Her book describes such a nonstop sex life that even in the homely setting of her Upper West Side apartment -- where the dimensions are human-rather than Hollywood-sized, where the record collection features Brahms, Benny Goodman and Peter, Paul and Mary, and where treasured photographs of Winters with John F. Kennedy and Eleanor Roosevelt loom large on the wall -- one half expects some matinee idol to come bounding out from under the coffee table in his underwear. But the most dramatic interruption is a housekeeper bearing iced tea, and Winters, in a billowy floral-print dress, talks about past vagaries with, well, literary detachment.

She calls the book "summer reading." Here she has gone and written about a lifelong struggle to be something more than a brainless twit, about a decade of indentured servitude in Hollywood doing films that still make her squirm, about her father's imprisonment for arson (he was later exonerated), and about a string of dead-end love affairs that left her, at least once, feeling suicidal -- and the result is "summer reading."

How have her old acquaintances responded to the book? Have they, too, greeted it as a harmless, hot-weather pick-me-up?

Yes and no.

"Burt Lancaster was a doll," says Winters. When Lancaster heard she was writing her memoirs, "He called me up and told me a hilarious story that I had forgot about. I had a very long, rather tragic affair with him . . . We had adjoining dressing rooms at Universal and I was in 'A Place in the Sun' and he had ordered dinner and I'm looking at my watch and he's explaining the whole blacklist thing to me which I didn't understand . . . So I had a big scene to do and finally in a very meek voice I had to say to him, 'Burt, could you give me a pamphlet on it and make love to me and let me go home?'"

William Holden was less supportive. Their affair, as Winters describes it, was a Christmas Eve thing, strung out "Same Time Next Year"-style, over about seven years. They would rendezvous at studio Christmas parties, address each other as "Miss Winters" and "Mr. Holden," and scarcely meet outside the holiday season.

L'affaire Holden was interrupted by Winters' second marriage, to Vittorio Gassman. Winters claims she sent a look-alike friend that year who reported back that Holden was "so drunk he didn't know the difference." After the recent serialization of her book in Ladies Home Journal, she and Holden did a film together, and he suggested, cooly, that now they should call each other by their first names. "I think he kept me out of a scene that I was supposed to be in," she adds suspiciously.

She has decided she could have left Holden out of the book "and it would have been just as successful." Their relationship was an accident, she says, and she is "ashamed of it."

Errol Flynn, of course, is dead, so his reaction cannot be know. But if Flynn were alive in 1980, he would have a lot to respond to before he got around to Winters. The accusation that one has been a Nazi spy tends to put other things into a gentler perspective.

On the Nazi front, Winters has come to Flynn's defense -- after a fashion. "Absolute nonsense!" she says. "He wasn't that good of an actor. I would have know." Besides, "even to be a Nazi you have to want to be dedicated to something. His life was completely the pleasure principle."

She met Flynn, according to the book, on a double date with Yvonne De Carlo and Clark Gable. "Yvonne," she writes wryly, "said she thought Errol really liked me, so she would sacrifice herself and take Gable."

The advertised reason for their get-together was to screen a movie in Flynn's living-room. But about an hour into the film, "Mr. Flynn must have pressed a button because a twelve-foot sliding panel had slid open, and there on a raised platform was a huge bed covered with cream-colored satin sheets and pillows, the top sheet turned back, ready. As I gazed in stunned fascination, I saw that around the bed there were plants, books, scripts, telephones, a small wet bar, and on the other side were an icebox, a radio and a phonograph. On the ceiling above the bed was a huge mirror, and as I watched, the mirror slid away, and I could see the stars and the moon through a flowering magnolia tree."

So none of her former companions in indiscretion has made a particular fuss over the book. But how does Winters herself feel about letting it all hang out?

"I feel it's released me," she says, giving co-credit to years of psychoanalysis. "I feel like I'm just starting to live. I'm writing. I'm not afraid like I used to be . . . I can now go to school and study the novel."

Not that she has abandoned acting: She is on her way to West Germany to do a movie produced by Werner Fassbinder. She also hopes to make her debut as a movie director with a project called "Thunder LaBoom," a story about topless/bottomless bars. But the plans that seem to matter most are writing plans. These include a second volume of memoirs and a novel called "Coming of Age in the Star Factory," which also sounds rather autobiographical and which, she hints, may not follow all the same laws of good taste that guided the writing of "Shelley -- also known as Shirley."

Good taste is not the characteristic of the book that grabs the reader first. But amid the torrent of candor, Winters has been, here and there, quite circumspect. The same author who tells how Marlon Brando vacated her bed at 5 a.m. one morning and hid on the roof because Burt Lancaster was paying an unexpected visit will guard to the death the identity of her first husband. He is a "private citizen," she explains. Even her daughter, a pre-med student at Columbia, is referred to by an untraceable nickname.

Born in St. Louis, the daughter of Austrian immigrant Jonas Schrift and Rose Winter of St. Louis, Shirley Schrift moved to Brooklyn in the late '20s. Her father opened a harberdashery, and after a fire in the store was convicted of arson and spent a year in Sing Sing. She became interested in theater in junior high school, and auditioned for the role of Scarlett O'Hara in the celebrated David Selznick/George Cukor nationwide talent hunt.

After early success in beauty contests, community theater and modeling. She attended New York's New Theatre School in the '30s, did the Borscht Circuit and vaudeville, and finally got to Broadway, where she was spotted by Columbia Pictures and signed to a contract. During World War II, her first husband, an airman, was sent to England. She moved to Hollywood and showed up at Columbia, her first studio.

When a wise old hand advised her that "Shirley Schrift" was a fine name for Brooklyn but not for Hollywood, she invented "Shelly Winters" from her favorite poet and the plural of her mother's maiden name.

Shirley was a naive but intellectual eager girl with an intense interest in politics. Shelly, on the other hand, was a "cutsie pie" who "used to go 'bippity-bip.'"

Shortly after her husband returned from the war they were divorced, and she switched to Universial.

"I needed to sleep with a movie star so I should think I'm a movie star," she says. And if she drifted off-course, the Universial publicity department was always there to set her straight. After a few dates with Stanley Kramer -- then a "very nice" young film editor -- she was told, "You shouldn't be seen with editors." And she wasn't, ever again.

Yet even in her dizziest dizzy-blond period, she sought the company of intellectuals -- particularly writers, whom she seems to have regarded as another, higher species. At MGM, she met Christopher Isherwood, Dorothy Parker, Thomas Mann and Budd Schulberg, and "the only thing I really resented about Metro was that I had just missed knowing Scott Fitzgerald, who had been fired a few years before."

At Hollywood literary gatherings, she writes, "if the conversation got too tough I would hide under the piano." And she recalls once paying tribute to Dorothy Parker as "my most favorite author in the world," and getting this semi-classic retort: "Well, if I'm your favorite author, then you really must be from Hollywood because that means you're practically illiterate."

Is it possible that as she undervalued her own mind, she may have overvalued the minds of some in the intellectuals she revered? The idea seems to intrigue her.

In 1949, she roomed briefly with Marilyn Monroe, and they made a game of listing the most desirable men in politics, music, science and literature. Monroe's list included Jean Renoir, Ernest Hemingway, Charles Laughton, Arthur Miller and Albert Einstein. Winters' included Laurence Olivier, Cary Grant, Albert Schweitzer and Ralph Bunche. Winters soon met Olivier, but it was all business. "It would be like sleeping with Adlai Stevenson," she told Monroe. "Oh, boy and you think I have problems about sex!" Monroe replied. (Years later Winters adds unexpectedly, "when Adlai Stevenson was U.S. Ambassador to the United Nations, I was his hostess at an official dinner in the Waldorf Towers . . . problem solved.")

Today's Shelly Winters speaks gratefully, about a "tremendous freeing of acknowleging that I have a brain." She does not speak, or write, about any deep anguish on the subject. So the public is left to wonder if the true story may have been, from time to time, a bit less giggly than her current account of it.

Her 20-year war with overweight could be a sign of that. In any case it is one thing she takes seriously up to a point. She has become involved in "Over-Eaters Anonymous" -- information that perks the attention of her old friend Arthur Laurents, the playwright, who has stopped by to pitch a new play and, as the interview lingers, has been thumbing through a pile of books on the coffee table.

"Ovaries Anonymous?" asks Laurents incredulously.

"Over-Eaters Anonymous," Winters repeats. "You say, 'My name is Shirley and I am a compulsive over-eater.'" But she has trouble with some of the group's requirements. "I can't join hands and say, "Please, God, don't let me have a cookie.' I mean, if there's a God, he's busy with more important things."

If her book leaves some questions unanswered, that's all right: The sequal in on the way. There was some struggle in the metamorphosis from actress to author after Morrow & Co. gave her a $75,000 advance, but once she got going, she got going.In the end, she wrote 1,200 manuscript pages and had only reached the year 1956 when she and the publishers decided to come up for air.

Her Broadway triumph in "A Hatful of Rain," her third marriage to Anthony Franciosa, his unfortunate run-in with an inquiring photographer -- these events, and more, are still to come. The photographer wanted a picture of Winters and Franciosa as newlyweds, and after a long colloquay of "I can take your picture" (the photographer talking) and "No you can't" (Franciosa talking), "Tony took the camera away and broke it and socked him, and he went to jail for 30 days to the honor farm," she says. "That was the end of Tony as a sane person, of the marriage, of everything. It just murdered him. It was a terrible experience . . . . That's the next book."