It's Friday night in a small plane bound for Allentown, Pa., and Eunice Kennedy Shriver is asking questions.

She wants to know about Jane Austen, though no subject, it would seem, could be less relevant to Shriver's immediate interests -- Special Olympics and the mentally retarded -- than a 19th-century English novelist.

But since her questions have brought her to her seatmate's favorite author, she wants to know: What was Jane Austen like? Was she the one with the nasty father? Were her books well received when she wrote them? The questions keep coming until, finally, an answer about "Persuasion" -- that its heroine was deemed a "nobody" and a "nothing" by her family and her own selflessness -- seems to satisfy her.

Shriver's lanky body sinks into a slouch. The briefing notebooks -- filled with categorized information on the Pennsylvania Special Olympics, whose games she will visit in less than 12 hours -- slide a little closer to the edge of her lap. Her right hand raps absently at the window. Several thousand feet above the ground and buckled in, she takes leave of the conversation and turns to stare out the window, into an empty darkness and an inviolable silence.

She sits there, dressed in a white-on-blue polka-dot outfit, with little, lacy bobby socks creeping out of a pair of blue loafers. Bobby pins dangle in her tousled thick hair, loose and useless like so many extra twigs in a nest.

Long minutes pass.

"That's interesting," she says suddenly. "I find that very interesting.

"You see, that's how the children are -- that's what happens to them," she says. "So often they are isolated and overlooked, even by their own families. Pushed aside by society."

She leans toward the floor, rummages through a bag, pulls out a black notebook and prints on the top of a page "GET PERSUASION."

Ethel Kennedy, Shriver's sister-in-law, says "she's just got her own spin on everything. It's a little different from everyone else. Like putting a spin on a billiards shot." She is constantly splicing together the most unlikely subjects and ideas -- mixing something that was squirreled away in her mind years ago with a new scrap of information: Jane Austen and the mentally retarded. Abigail Adams and young women of the '80s who whine about balancing family and work. Or "E.T." and the mentally retarded.

" 'E.T.' I just loved 'E.T.', didn't you?" Shriver says. "After I saw it, I wrote to Steven Spielberg -- to see if he would do a {television} spot for Special Olympics. Because, I thought E.T. -- you know, that's how the children are sometimes ignored. Hidden. People are ashamed of them."

The Genesis of a Cause Today Special Olympics is the world's largest year-round program of sports training and competition for children and adults with mental retardation. It reaches more than 1 million athletes, ages 8 and up, and is run by more than half a million volunteers. Shriver is its founder and chairman.

This week, during the VII International Summer Special Olympics Games in South Bend, Ind., more than 4,500 Special Olympics athletes representing every U.S. state and more than 70 countries will compete in such sports as aquatics, basketball, bowling, soccer and softball. Last night's opening ceremonies will air tonight as a two-hour special on ABC.

But 25 years ago, Special Olympics was a back-yard summer camp with a three-digit enrollment. The Shrivers, who married in 1953 when Eunice was 31, lived on a farm in Rockville -- Timberlawn -- that in 1963 became Eunice Shriver's camp for mentally retarded children. The numbers were humble: 100 high-school-aged volunteers; 100 mentally retarded children; "about five" paid instructors; a week-long training session; one swimming pool; sundry horses, dogs, fields and barns; and, Shriver says, "just lots of fun things."

Sargent Shriver, first director of the Peace Corps and now president of Special Olympics International, says the purpose "was for my wife to see what the truth was. What were the facts? What could the mentally retarded do? In that time you had to see for yourself . . .

"So she tried everything. She had 'em on horseback, swimming, on a trampoline, shooting bows and arrows, climbing trees, building tree houses, playing tennis ...

"It wasn't that she was sitting up there with a magic wand waving to everybody, 'Now do this! Now do that!' She was out there. She'd be in the swimming pool, holding a mentally retarded {teen-ager} up to see whether she could teach him how to kick, how to swim. Whether she could get him through the water."

There were signs before Timberlawn that Eunice Shriver would devote herself to people with special problems. After earning her bachelor's degree in sociology at Stanford University, she worked first for the State Department reorienting American POWs after World War II, and later for the Justice Department as coordinator of the National Conference on Prevention and Control of Juvenile Delinquency.

But before all that there was Rosemary, three years older than Eunice and, as the family's euphemism goes, "slow to learn."

Edward M. (Ted) Kennedy, the youngest of the nine Kennedy children, remembers.

"It always seemed that Eunice reached out to make sure that Rosemary was included in all activities -- whether it was Dodge Ball or Duck Duck Goose," he says. "Eunice was the one who ensured that Rosemary would have her fair share of successes."

Timothy Shriver, 27 and the middle of the Shrivers' five children, says his mother -- "always committed to the possible" -- saw in Rosemary, now 68, "somebody who was succeeding, as opposed to somebody who was barely doing what she could with her limitations."

"I suppose," Eunice Shriver, 66, says, "the fact that I had seen my sister swim like a deer -- in swimming races -- and do very, very well just always made me think that they {the mentally retarded} could do everything."

But to draw a straight line from Rosemary Kennedy to Special Olympics -- or even to the Joseph P. Kennedy Jr. Foundation for the retarded -- is, according to Eunice Shriver, a mistake. It wasn't because of Rosemary, she says. "And I think that's important. Certainly, if you have a sister who learns slowly, you are obviously aware of certain things -- insights that you wouldn't have if you never had a sister who is slow to learn. But, would I have gone into this for her, and do I run around for her? No."

Battering Down Barriers Working his way toward an explanation of Eunice Shriver's ability to see the positive side of retardation, Sargent Shriver says, "She just didn't believe that there were human beings who were as useless or hopeless or whatever the right word might be as the mentally retarded were thought to be 40 years ago."

But 40 years ago hopelessness was indeed the state of the science. The goal of medical intervention, says Dr. Robert E. Cooke -- a specialist in mental retardation and professor of pediatrics at the State University of New York at Buffalo -- was "custodial care and keeping people moderately alive."

"When I was a medical student, which would have been in the '40s, the general teaching regarding the mentally retarded was that they all belonged in institutions," Cooke says. "Retarded people and Down's {syndrome} people were just not the sorts of individuals who could benefit from the usual social contacts.

"And the notion that a Down's individual could run or jump or do gymnastics or participate in sports was unthinkable. They'd die. Somehow, constitutionally, no way could a Down's person run a race, or run a mile."

Then there was the idea that losing and disappointment would not be good for retarded children. The mention of it brings Shriver to a simmer. "Yeah, well, I heard a lot of that," she says. "That's a lot of baloney. What proof have they got that as a group of people they can't take losing? Who? Where does it come from, that idea? Somebody cries because they lose? I can tell you 50 people who cry -- I go and watch my own kids cry when they lose."

The change in attitude -- the recognition of the value of competitive sports for the mentally retarded -- has been, Cooke says, "just phenomenal. When you think it is expected that they can run, that they will compete, and that people are even interested in their {race} times -- to a very large extent, this is Eunice's accomplishment."

Great Expectations Behind the accomplishment -- be it Shriver's or a Special Olympics athlete's -- is expectation. The word runs through Shriver's life, present at every chronological turn, threaded through what others say about her and what she says about herself. "There's no sense {with her} that you can't do something very important," says Sargent Shriver. "And the back side of that is that you are expected to do damn well. You've got no damned excuse not to do well.

"And the retarded -- well, I think my wife just expected them to do well. There's no mollycoddling in her. That's true with our own kids and with the mentally retarded."

Nor was mollycoddling a part of her own upbringing. Achievement was expected: She was part of a financial and political dynasty -- daughter of businessman and diplomat Joseph P. Kennedy and Rose Fitzgerald Kennedy; sister of President John F. Kennedy, assassinated in 1963, and Sen. Robert F. Kennedy, assassinated in 1968, as well as Sen. Edward Kennedy.

In Rose Kennedy's 1974 memoir "Times to Remember," Eunice Shriver describes an aspect of her childhood that Rose called "training them {the children} for excellence":

I remember she {Rose Kennedy} would take us ice skating in Bronxville, and you just wouldn't go skating off into the blue yonder: She'd say, use your right leg or use your left leg better; again it was this terrific drive, she wanted everyone to do their best. There was quite a little pressure around. If you weren't doing very well there weren't any excuses for it. She'd say, you just get along there, don't be stupid about it, or something like that ...

And she was always very energetic and expected us to be. Today, children stay in and watch television or listen to radio or records, but we were packed up and out we'd go, no matter what the weather was ... so far as I can remember the first time in my life I ever stayed indoors was when I was in my thirties and had a baby and had to stay in. And I walked around in the hospital and thought, How odd, some people stay in and read all day ...

Ethel Kennedy remembers a story about Shriver's drive to excel:

"Eunice prides herself on her sailing ability -- she races. And one summer her boat wasn't going well. Like everything else she does, she got involved in it and she started to investigate. She climbed below {deck} and discovered heavy bricks in the bottom, beneath the floorboards -- very, very heavy, like gold bars. She's so competitive that she probably thought -- well, I don't know what she thought -- that somebody was trying to sabotage her. Then and there, she threw the anchor overboard and she and the children tossed the bricks out of the boat. As it turned out, the bricks were the ballast.

"Later," Ethel Kennedy concludes, "she discovered that they were worth something like $3.75 each -- and the rest of the summer those children were seen diving for them."

The Persistence of Vision She's impossible. Autocratic. Shy. The most interesting and exciting woman in the world. Funny. Difficult. Curious. Bright as hell. Irreverent. Spiritual. Eccentric. Sensitive. Insensitive.

People say the most contradictory things about Eunice Shriver. But on one thing they agree: She knows what she wants and she is relentless in the pursuit of it.

"She has a great sense of priorities in her life," says longtime friend Donald Dell, a Washington sports attorney who was Sargent Shriver's assistant at the Office of Economic Opportunity in the '60s. "Whereas most people worry about 'What should I do with my life next year?' and 'Where do I want to go?' -- for Eunice all that stuff is stuff. With her it's family, religion and causes."

"She has, through her persistence, strength and the fear she creates, driven people to participate who otherwise wouldn't have. They might not like it, but they are better for it," says David Burke, an ABC News vice president who formerly was administrative assistant to Ted Kennedy. He considers his own enlistment in her causes and laughs: "If I get to heaven, it will be because she drove me to it."

"Sure," says friend Ann Buchwald. "She's very bossy. Very determined. Hurries. And drops things. And says only the important things. Talks only to the important people. And why not? She has only a limited energy. If she could put 13 more hours into the day, she would. Meanwhile, she wastes not a minute."

Eunice Shriver operates with a kind of high-octane fervor. "We don't usually sit and talk," Deeda Blair says of her friendship with Shriver. "We would swim and talk while were swimming. Or we would walk rather briskly and talk. Or we would be driving somewhere to see something and do something and talk along the way."

Even when she sits, she's always moving. Swiping at her hair. Batting the bangs out of her way. Gnawing at one finger or another. Attacking the cluster of diamonds and sapphires on her ring finger, twirling it around and around.

And when she's moving, she expects others to move. She still seems vexed, for example, by a Timberlawn camp episode: "We had a day for parents and they came and sat by the pool. They were supposed to play sports, but they all sat around the pool. I was so mad 'cause I wanted them all to participate. But they sat by the -- I suppose it was their day off and they lolled by the pool."

The Cheerleader The 25-meter freestyle swim behind him, the Special Olympics athlete, wet and draped with towels, steps up onto a plywood box, throws a tightly clenched fist into the air and shouts, "Eat your heart out, Stallone!" And then he shouts again: "Eat your heart out, Stallone!"

Before him stands Shriver, ribbons dangling from her hand. "The gold one. The gold one," he says, swelling with adolescent pride. Shriver pulls out a gold medal and hangs it around his neck. "Here you go," she says. "Well done. Terrific."

The Pennsylvania Special Olympics summer games echo with Shriver's "Well done ... well done." She spends the day -- a dry, hot Saturday -- roaming from pool to playing field, one minute handing out medals, the next sitting on the bleachers talking to a corporate sponsor, the next disappearing into a crowd of children. She smiles with them. Pats their arms. Urges them on. "You look in good shape." "Is this your first gold medal?" "Are you getting better?" "Practice every day." "Keep it up."

At the end of the afternoon, as she sits on a bench and talks to a softball player, one side of Shriver -- restless, elusive and abrupt -- gives way to another -- calm, settled and delicate. "Do you read? Do you want to learn to read?" And Annie, an affable, red-haired young woman of almost 20 who pitches a mean softball, shakes her head, smiles and looks at Shriver.

"No," Annie says. She can't read. She doesn't know why not. She wants to, but she just can't.

"Do you read signs?" Shriver asks. "Do you know your address?" "Do you know what street you live on?" No, no and no.

Eventually Shriver has, in her notebook, Annie's full name and, from another source, her address.

Annie has, from Shriver, the promise that she'll investigate the possibility of a tutor or a reading program, as well as a bit of advice: "What you oughta do," Shriver suggests, "is go home and memorize your address. If you said it to yourself five times a day, I betcha you could learn it."

Esthetics and Essentials Shriver, a devout Catholic, "would have made a wonderful abbess," Ethel Kennedy says.

"But she would have made a terrible cook," she adds. "She's totally oblivious to anything worldly. Sort of like Eleanor Roosevelt -- she's into the world of ideas."

The esthetic expressions of self exist in her life like a necessary postscript, neither completely omitted nor completely incorporated.

Clothes, for example. "Her get-ups are beyond belief," Ethel Kennedy says. If someone should register a comment or criticism, "she just looks at them like 'What are they talking about?' and goes on about her business."

And food. It's possible to spend a day with Shriver and see her nibbling at nothing more nutritious than a handful of graham crackers, cookies or bread -- always in a kind of neutral, distracted manner.

"Lots of things that are terribly important to other people and that are life-enhancing, like delicious food and pretty flowers and well-organized households and that sort of thing -- I guess Eunice likes all that, but she doesn't care about it intensely, in an obsessive way," says Deeda Blair. "You can go {over to the house} and things will be in wild disorder; and sometimes they will be spruced up and there will be a very pretty party. But nothing like that is terribly important to her."

Blair remembers visiting the embassy in Paris when Sargent Shriver was ambassador to France during the Johnson administration: "You'd walk in the front door and instead of being grand and imposing, it would be full of bicycles and motorbikes and skates and skis."

The tone was one of youthful, cluttered Shriver vitality. Bobby and Maria, the two older children, were teen-agers and scattered behind them in age were Timothy, Mark and Anthony.

And if, for a formal event, the skis and roller skates were temporarily contained in a closet, the children were not. Often, they were the life of the party. One reception Blair particularly remembers honored a group of African ambassadors. "All in these wonderful robes. And all these little children were going around, passing trays of hors d'oeuvres, sort of half of them falling off," she says, raising her arm and dangerously tipping an imaginary tray of food.

The Shrivers had put a trampoline in the embassy garden, she says. "And the children would pull and tug and get these African ambassadors to jump up in the air on the trampoline. It was absolutely so unconventional."

'The Happier Course' "Let's face it," Ethel Kennedy says, "she would have made the best president of the United States."

"I mean," Sargent Shriver says, "she would have been a terrific United States senator."

"That's nice," she says quietly, when told of the many people who believe she could have held public office. "I think my brothers have done extremely well and enough. That's enough." She laughs lightly. "Enough," she says again.

"I really wanted to work with children," she says. "You can't do it -- well, now, much more, because there are so many committees, but you do an awful lot of other things. And I wanted to devote all my time to the children. In Congress, you have to do 50 other things before you get there, then once you are there, you have to do so much."

Then, almost inaudibly, she says, "But that's nice." What they said, she means.

And she squirms out of the thought: "I chose the happier course as far as my life -- no regrets."

The No-Nonsense Hostess Art Buchwald most admires the hostess in Eunice Shriver -- the woman who "throws people out of the house at 10 o'clock because she's tired and she wants to go to bed."

Donald Dell laughs and talks about "the old coffee trick": At the conclusion of dinner, Shriver announces that coffee will be served in the living room. The guests file in, the maid serves the coffee, and everyone asks "Where's Eunice?" Eunice, of course, has gone up to bed.

Her finest party-ending moment may have been during the mid-'50s in Chicago, where Sargent Shriver was managing the Merchandise Mart, one of the Kennedy family holdings. It was, as former ambassador William McCormick Blair remembers it, the Shrivers' first formal party:

"We all got there promptly," Blair says. "No Eunice, as I recall. Or Sarge. That's often the way. They were busy doing useful things, and she'd been working all day on some important project.

"Finally they came. And we had a wonderful dinner and evening. After dinner -- it couldn't have been much after 10 o'clock -- Eunice kept saying to me, 'When is everyone leaving?' I said, 'Well, Eunice, this is a black-tie party. It's your first party. Everyone is having a good time. It's a wonderful dinner. And people don't go home, usually, until around 11.' She sort of rolled her eyes at that.

"Finally, in a loud voice, she said, 'I've got a wonderful new game to play.'

"Everybody looked horrified. Eunice likes playing games -- charades. But this wasn't going to be charades. She said, 'Everyone stand up and close your eyes and put your hands on the shoulder of the person next to you. Then we'll all start marching. Going round in circles.' We all started and the next thing we knew, she said, 'Now you can open your eyes.'

"We were all standing out by the elevator. And she said, 'Good night.' "