Jennifer O'Neill was the pedestal girl of 1971, the bereaved war bride in "Summer of '42," crisp and lyrical as a snapping flag, the unobtainable obtained.

In 1979, Jennifer O'Neill loves Luchino Visconti. He is dead. She is eating asparagus and tomatoes vinaigrette and drinking Pouilly Fuisse in a suite over 16th Street. A haze of fascination comes over her face.

"I was in Deauville when my agent called and said Visconti wanted to see me in Rome, about playing the countess in 'The Innocent.' Of course I'd heard about the part, I thought Jacqueline Bisset was going to do it. I went right away.

"It was a four-hour driver from Rome. All the way I was telling my agent, 'I don't do nude scenes.' And he was going crazy, he was saying 'This is Visconti! You can't make demands!'

"Visconti was sitting in a garden, in back of a villa, in his wheelchair, I sat down in front of him. He said: 'Have you read the script?' I said 'Yes.' He said: 'Do you like it?' I said: 'Yes.' He said: 'Good. We start fittings on Monday.' Afterwards, I told the producer I didn't do nude scenes. He said: 'Don't worry.' and there was never a word about it.

"He never even directed me. There were no rehearsals, we never discussed the role. We'd have dinner and talk about horses - he loved horses, and so do I - and flowers. Flowers! He always had them around him. One morning, we had to wait for two hours until he found just the right shade of roses to put in a corner."

How often does a woman - especially one who at 31, has been through four marriages, and wants to make a "faintly" autobiographical movie called "Fanny and the White Knight" - meet Luchino Visconti? He was totally decisive, intuitive, and confident in her, demanding and liberating at the same time - perfect, by her accounting.

"Well," she says, rummaging in her asparagus and tomatoes - she seems embarrassed for a moment - "He was a homosexual."

"The Innocent" was Visconti's last movie. He died in 1976. It opens here Friday, a redolent chiaroscuro chronicle of jealousy, infanticide and suicide in upper-class, turn-of-the-century Rome. O'Neill plays the widowed mistress who both catalyzes and survives these disasters. It's a lively performance amid the art-film sluggishness, like the smell of a cup of coffee amid the frangipani.

Maybe O'Neill has a flair for widowhood, first in "Summer of '42," and now in "The Innocent." She's still equally unobtainable, a woman who knows too much - a woman who, for every man, will be an accident he'll never understand.

Her hair is filled with gray, her own: "I've had it since I was 15. When I tell people I don't frost it, they ask me why I don't get rid of it."

At 15, too, she started a modeling career in Manhattan, moving quickly to the covers of Vogue and Seventeen. At 16 she moved away from her English mother and Spanish-Irish father, and into her own apartment. At 17 she married, and at 19 had a daughter, Aimee.

"I never saw myself as beautiful.I realized that my bone structure was photogenic in a certain esthetic sense, but I wasn't popular, nobody asked me places."

"The day I left my parents' apartment, I went to the pound and got a dog." she says, and this unravels a long string of stories about her dogs - all females, who've accompanied her all over the world, though not to Washington because of some baggage problem with the shuttle - especially Bett, the new one, a German shepherd.

"I keep looking around for her. I even took her to Iran when we were shooting 'Caravans.' They don't like dogs there but I even took her to the palace when the princess invited me - you should have seen the faces of the guards, you should have seen them."

And during the filming of "The Innocent," her Samanths ran off: "I was running through the streets of Rome in full costume, I was sobbing, I couldn't find her. When I got back to the set it was obvious it would take an hour and a half to put me back in shape for shooting. They said: 'You'll have to tell Luchino that yourself.'

"We were in this palace. He was sitting at the end of this huge room, in his wheelchair, under an arc light. I had to walk through this crowd of extras in formal costume, all of them watching me. I tired so hard to keep my composure. Finally I got there, and blurted out.'I lost my dog . . .' And Luchino took my hand and said 'We'll find your dog.'"

But they didn't. Although a year later, she landed in Rome "with this funny feeling. I drove around the city for two days looking. Finally, I went to a pound back near the airport. They showed me all these males. I said do you have any females? They brought out a dog and told me she'd been born at exactly the same time Samantha disappeared. I looked at her and knew she was mine."

Now, on her farm in Bedford Village, N.Y., O'Neill trains attack dogs, and sells them. They make her feel secure, she says. And she rides and shows horses, and is quick to hope that a questioner doesn't see "that old phallic business" about women riding horses.

She wants to make her while-knight movie on the farm - she's even going to have him riding a white charger. "But you'll never see his face. It's a movie about the possibility of romance, that it really is possible," for all that her two most famous movies suggest that it's happenstance.

"My parents fell in love in England during the war. He was a war hero, I never knew that, but he was one of the people who was in the great escape," she says, referring to the POW break-out celebrated in the movie of the same name.

"Someday I'm going to make a movie about him, too. He and my mother are still in love with each other, it's been volatile, but they are, and I grew up thinking that it was always like that, I guess."

It was one of the painful illusions she tried to work out with years of "astral projection, astral travel - night school, I used to call it," she says, riding down in the snuff-box elegance of the hotel elevator.

Stepping through the hotel's front door she pauses: "You can come awake in your dreams."

A limousine glides up the driveway, and she's already stepping in when the question is asked: has she discovered any previous lives? Yes, of course. Such as . . .

Only her face, and that strangely gray hair, are visible now in the Cadillac gloom. She thinks for a second.

"A pharaoh," she says. CAPTION: Pictures 1 and 2, Jennifer O'Neill; by Margaret Thomas-The Washington Post