HARRY TRUMAN called her "the first lady of the world." For a generation of Americans, she was far more than Franklin Roosevelt's wife. She was part of the national identity.

And this fall, as her 100th birthday nears -- on Oct. 11 -- America is remembering Eleanor Roosevelt again.

Her famous tall, bucktoothed, gray-haired image appeared constantly in newsreels and magazines: chatting with Khrushchev, speaking before the United Nations (to which she was one of our original delegates), campaigning for Truman, Stevenson, Kennedy, narrating "Peter and the Wolf," rubbing noses with Maoris, wearing that billed cap of hers during World War II and visiting soldiers literally in their foxholes, tripping around the world as an informal ambassador to various world leaders -- more than that to the vast throngs of ordinary people who clustered to her wherever she went. And she went everywhere.

Many of these images will be seen in a new Smithsonian exhibit, opening today at the Museum of American History. Last night close to 1,000 people heard a unique tribute at the museum: a newsreel interview augmented by live dialogue between National Public Radio host Susan Stamberg and actress Jean Stapleton in the persona of Eleanor Roosevelt, complete with broad "a."

Asked about her life and ideas, "Mrs. Roosevelt" replied with authentic quotes. On FDR's election in 1932: "As I saw it, this meant the end of any personal life of my own." On World War II: "I imagine every mother knew my feeling when I had to say goodbye to children during the war . . ." On talk of World War III: "This is by people who have no conception of war. We have not known what bombs dropped on our own soil would mean."

She also told of her first visit to St. Elizabeths Hospital here and of trying to get Cabinet wives to tour the Washington slums with her. Films showed her visiting West Virginia coal towns in the darkest Depression and Army hospitals in the war.

Once Stapleton, who has played Roosevelt in a TV special, hesitated and said -- still in the Roosevelt voice -- "You know, I prepared very carefully this speech, but I'm missing Page 31." To a roar of laughter and applause, she was given Stamberg's copy. It was Eleanor to a T.

For those of us too young to have known Eleanor Roosevelt, this celebration may open new vistas on the meaning of politics and feminism and everyday integrity. For the rest of us, it will be a reunion.

For we felt her presence everywhere, through her books, a daily syndicated newspaper column and untold numbers of letters to the great and the obscure, through her lectures and speeches, through her recorded reactions -- always cogent, considered, humane -- to events of the day, even through the TV commercial she made for a margarine firm so she could buy CARE packages with the $35,000 fee.

The public's fond acceptance of her as an institution often took the form of gentle amusement. A New Yorker cartoon showed two miners, deep in a dark shaft with their headlamps on, looking up in astonishment to mutter, "My God, here comes Mrs. Roosevelt!"

There were those who detested her. Her high-pitched grande-dame voice was easy to mock, and the buckteeth -- finally replaced after an auto accident, much enhancing her appearance -- made her all too easy to caricature, but woe betide the comedian who dug too deep. A flood of defenders would rise up from every corner of the country. Columnist Westbrook Pegler, who made a career of his hysterical attacks on her ("Eleanor the Great," "La Boca Grande," "deserves far less respect than any conventional woman"), eventually lost his readership and vanished into obscurity.

She was proposed for vice president as early as 1948, later for the presidency and the Nobel Peace Prize. Right up until she died, in 1962, she was consistently voted America's "Most Admired Woman," above Jacqueline Kennedy, Queen Elizabeth II and Mamie Eisenhower. Such a force was she in the world during the 17 years following FDR's death that people tended somewhat to overlook her other career as first lady. Before her, presidents' wives had kept pretty much to the White House, presiding at dinners and giving their names to committees. Eleanor Roosevelt was the first to hold weekly press conferences -- exclusively with women reporters, who had long complained about being left out of Washington's political inner circle.

She lectured around the country on the United Nations, the New Deal, poverty, racism, and she had her own radio program. She organized a social experiment in cottage industry, making furniture at Val-Kill, on the Roosevelt Hyde Park estate. For years she was the crippled president's physical contact with his people, driving to the most remote corners of the nation in her little blue roadster to talk with the invisible poor, the minorities, the unjustly treated, for whom she could exert powerful pressure on the administration to take action.

But it was after FDR's death that she really took off.

As the first delegate President Truman named to the United Nations, she led the fight to draft the U.N. Declaration of Human Rights at a time when American liberals like herself were discovering Soviet Realpolitik the hard way.

Her gradual adjustment to this fact of life in her bitter confrontations with Andrei Vishinsky, the prosecutor of Stalin's purge trials -- particularly over the right of individual choice versus forced repatriation of Europe's million-plus displaced persons -- is chronicled dramatically by Joseph P. Lash in "Eleanor: The Years Alone," the sequel to his "Eleanor and Franklin."

It was an era when liberals such as Secretary of Commerce Henry A. Wallace could idealize the Soviet Union to the extent of quitting the Truman administration over its "get tough with Russia" policy.

Yet "not even her son Elliott's espousal of an attitude toward Russia very similar to Wallace's checked her maturing conviction that Soviet Russia was primarily responsible for the breakup of Allied unity," Lash writes. ". . . She had begun her career at the United Nations bending over backward to show the Russians she was ready to meet them halfway. By 1949 she was stating publicly she would 'never again' compromise, 'even on words. The Soviets look on this as evidence of weakness rather than as a gesture of good will.' "

Resigning from the United Nations in the Eisenhower administration, she did volunteer work for the American Association for the United Nations until her reappointment to the delegation by President Kennedy. In the interim the AAUN gave a party for her. No Eisenhower people attended, but U.N. statesmen Ralph Bunche and Dag Hammarskjo ld did -- and so did Vishinsky.

She could be implacable. When Carmine De Sapio, the Tammany Hall boss, spoiled Franklin Jr.'s bid for the New York governorship, she retaliated. It took her and her allies three years, but she brought De Sapio down. Then there was the time she took on Cardinal Francis Spellman of New York over federal aid to parochial schools. He attempted to excommunicate her in the press, but took it all back when he got her polite, crushing letter: "The final judgment, my dear Cardinal Spellman, of the worthiness of all human beings is in the hands of God . . ."

Like her husband, she grew far beyond her hermetic upper-class heritage. Brought up with a Henry Adams-style anti-Semitism that somehow associated the new materialism and "new money" with Jewishness, as well as a casual ignorance of the people she used to call "darkies," she soon outgrew all that.

When Elinor Morgenthau was barred from the very social Colony Club in New York because she was Jewish, Eleanor Roosevelt quit the club. And when the DAR forbade Marian Anderson to sing in Constitution Hall because she was black, it was Eleanor Roosevelt's public resignation from the DAR that blew the episode into world headlines. She also crusaded passionately in the South -- against her husband's wishes -- to stop lynchings in the '30s.

Her centennial will be celebrated at a symposium at Vassar College Oct. 13-16, as dozens of speakers discuss her vision on everything from McCarthyism to Israel, from civil rights to peace in the nuclear age. They will also treat her self-discovery as a person and a leader.

And that is the part of the story that makes her most real to us.

She was an ugly duckling, a poor little rich girl, a Roosevelt whose beautiful mother called her "granny" and whose beloved, alcoholic father was banished by the family. She feared the dark, she feared dogs, horses, snakes and other children, she feared being scolded, she saw herself as "a solemn child, without beauty and painfully shy . . . entirely lacking in the spontaneous joy and mirth of youth."

Her parents died when she was a child, and she was raised by a grandmother who sent her off to boarding school in England. There she learned perfect French, German, Italian (years later she would translate a speech at the United Nations when the official interpreter panicked) and the high liberalism of her mentor, Marie Souvestre, from whom she discovered that lost causes, like the Dreyfus case, sometimes succeeded.

"Photographs of Eleanor at this period show a tall, slim, narrow-waisted girl," writes Lash, "with soft, wavy hair arranged in a pompadour and braided in the back. Her most distinctive feature was her eyes; blue, serene, and soft, in their gaze one forgot the overly prominent teeth and the slightly receding chin. Her soul, said Mlle. Souvestre, was a radiant thing, and it could be glimpsed in her eyes. Like her father, she had the faculty of concentrating all her attention and sympathy on the person she was with."

At 20 she married her distant cousin Franklin, a dashing, handsome, outgoing young man very much influenced by his rather overwhelming mother. Her underground warfare with Sara Delano Roosevelt ("My son Franklin is a Delano, not a Roosevelt at all!") lasted until the older woman's death 36 years later and surely had a great deal to do with the gradual emergence of Eleanor's own vigorous character.

The most important battle in this war was, as we know from the play "Sunrise at Campobello," the struggle over Franklin's future after polio stopped his career cold in 1921. Sara wanted him to retire from politics and the world in general to become a comfortable invalid country squire. Eleanor wanted him to move forward.

"Eleanor refused to treat Franklin as an invalid and did not allow others to do so," Lash writes. "The struggle with her mother-in-law was finally over. 'She dominated me for years,' Eleanor later said. Franklin's illness completed her emancipation 'and made me stand on my own two feet in regard to my husband's life, my own life, and my children's training.' "

The polio was the second major crisis in the marriage. The first had been the Lucy Mercer affair.

In 11 years of marriage, Eleanor had given birth to six children, one of whom died an infant. Too shy to seek contraceptive advice, according to her son Elliott, she forswore sex entirely. A few years later she found letters written to her husband by her former social secretary, the beautiful, patrician Lucy Mercer. Eleanor's world collapsed. There had never been another man in her life. She demanded a divorce, but Franklin refused. Lucy Mercer, a Catholic, would never marry a divorced man.

Finally the couple worked out a truce, remaining married but with separate bedrooms. Franklin agreed never to see Lucy Mercer again. It was 1918. Two years later Mercer married the wealthy Wintie Rutherfurd.

Years later, after FDR's death at Warm Springs, Ga., Eleanor learned that Lucy Rutherfurd had been at his bedside. The two had kept up the relationship for years, had been together at White House dinners when Eleanor was away. Worst of all, her own children and friends had conspired to keep her from knowing.

She survived that blow, too. She burned Franklin's letters to her, historic or not. "I have the memory of an elephant," she once said. "I can forgive, but I cannot forget."

Five years ago, the publication of her intimate correspondence with Lorena Hickok, a Washington newspaperwoman, led to much excited speculation by some about whether their relationship was lesbian. Others pointed out that the perfervid language in the letters was not at all unusual for the intense friendships that arose between women of that generation. The discussion eventually died of tedium.

What does seem memorable is that it was a close friendship, greatly valued by a woman who needed warm friendships. She did her Christmas shopping all year long, and when she died she left behind a closet full of presents, still untagged, for those she loved.

Brought down at 78 by a bone marrow disease and drug reaction, she fought against the tubes and needles and pills being used to keep her alive and succeeded in dying on Nov. 7, 1962, by herself. She was, as she once remarked, "a tough old bird."

She always said, when asked where she got her astonishing energy, that the trick was not to get too self-absorbed. One remembers her words to Harry Truman when she told him, "Harry, the president is dead," only a few minutes after she had learned the news herself. Truman turned to her, stunned, to ask, "Is there anything I can do for you?"

She replied, "Is there anything we can do for you?"

Adlai Stevenson, an old friend, said this:

"What other single human being has touched and transformed the existence of so many others? What better measure is there of the impact of anyone's life?"