IT WAS NOT an auspicious beginning. Joseph P. Lash, onetime radical and United Nations correspondent for The New York Post, thought he had a good idea. In his spare time, he had written a profile of U.N. Secretary General Dag Hammerskjold ("The Man on the 38th Floor") for Harper's and it had gone over big. "It interested people," Lash recalls today with typical understatement.

Flush with success, the jaded journalist tried to become the budding biographer. He went to his editor at Harper's and offered to turn the article into a book. The editor loved the idea. The people who published books at Harper's, however, did not.

Crestfallen but undaunted, Lash continued to search for a publisher. He quickly found one at Doubleday, which gave him a "small contract." Two months after Lash completed his manuscript, Hammerskjold was dead and the world was hungry for news about the man. Lash's book was published in a dozen foreign languages. Suddenly, he could look past daily journalism. "There were two beneficiaries from Hammerskjold's death," he quips today. "Khruschev and Joe Lash."

For Lash, his biography of Hammerskjold was the beginning of a career as a biographer unmatched by contemporary American historians. Since his days as the chronicler of his class at City College, biography was just something that "wasn't all that hard for me," he says. "It was something I rather enjoyed doing," he recalls, "I don't mean to sound snooty in saying it," says the product of the Brooklyn slums, "but it just comes naturally to me."

Few would dispute that statement. As a young radical hauled before the House Un-American Activities Committee in 1939, Lash became a special confidante of Eleanor Roosevelt. That friendship lasted until Eleanor's final days. Lash remembers running back to his room at the White House or Hyde Park after dinner to scribble down what he remembered from conversations with the first family.

With Eleanor's death in 1962, Lash quickly set down his personal memories. And when FDR Jr. went in search of an official biographer for his mother, he followed her unspoken advise and chose Lash for the job. The writer jumped at the chance. Almost 10 years later, Lash's winters in Hyde Park and the long hours with Eleanor's private papers culminated in the publication of Eleanor and Franklin. Critics hailed the work as an insightful biography of the first lady and, equally important, a ground-breaking study in the biography of relationships. Lash had maintained his objectivity--even while writing about a close friend and her husband.

LASH WAS HESITANT when President Horner first approached him to write the definitive biography of Helen Keller, Radcliffe '04. But there was something in the Helen Keller story that rung a bell--another relationship worthy of exploration. True, there had been many books before. But no author had the full access to the documents and letters that Lash found.

Each person's life, Lash believes, is in many ways the reflection of another's. "Very few of us grow up like the wild boy of Averon--in isolation," he says laughingly. "There is always an individual," he insists. "The friend--or it may even be the enemy--and we get our own identity in a sense from that person's eyes." What separates Helen and Teacher from the volumes that preceded it, Lash says, is his work on the relationship between the two women.

For Lash, therefore, the balance of the Helen Keller and Anne Sullivan Macy story was more than history. "I guess if I were starting life all over again and realized the pleasure I got out of writing biography," he says, "I would do some very serious work in training myself in psychiatry." Dismissing the idea that psychobiography is junk, Lash believes psychoanalyzing his subjects--something he does occasionally in Helen and Teacher--can be a very helpful tool in unravelling mysteries.

Using evidence available on the surface, Lash says, most of the writers that trod the historical ground before him concluded that Helen was somewhat shallow. They preferred Annie to Helen. The reason is simple, he says. "Helen was almost too good." Her world was one of friends and enemies, black and white; those who cared for her were good; those who slandered her Teacher were not. As Lash quotes Alexander Graham Bell, there was a feeling among those who met her that "if God undertook to be represented on the earth, it would be in the person of someone like Helen."

Annie, on the other hand, was much more complicated. She tempts writers, Lash believes, because "she had so many flaws and they were on the surface where you could get hold of them." Lash says he was "very conscious" of the natural bias toward Annie. Using the psychoanalyst's tools, he concludes in Helen and Teacher that Helen was forced into the position of drawing simple moral lines. "She knew how important Annie was to her," Lash explains. "She determined she would not allow any criticisms of Annie in her thoughts. That was the price she payed."

He chuckles and recalls when he began writing Helen and Teacher about three years ago. His seven-year-old granddaughter had come to Martha's Vineyard to visit him and when she learned of his latest project, she announced that she "knew all about Helen Keller." He asked her why. "Our teacher read us a book about Helen Keller," she responded. Lash says his granddaughter--and others like her--remember the story of Helen Keller because she ranks among a number of select historical figures that people can identify with. "It's very easy to understand why," he says. "Here is this woman deaf, dumb and blind and everyone has the same reaction. And it's the reaction that I had--who am I to complain?"