John Hersey was thirty-two when The New Yorker published “Hiroshima,” his massively influential article on the atomic bombing. PHOTOGRAPH BY DMITRI KESSEL / THE LIFE PICTURE COLLECTION / GETTY

Seventy years ago, this magazine devoted its entire August 31st issue to an article by John Hersey titled “Hiroshima.” It became a landmark in journalism, in publishing, and in humanity’s awareness of itself and its own awful potential. It detailed the lives of six people who had survived the American atomic attack on the Japanese city, which had taken place a year earlier. Much reporting had been done in the aftermath of the bombing, most of which was technical or philosophical, focussing on the power of the weapon or on the wisdom of using it. In choosing instead to report on individual victims, to follow the unfolding of their lives in minute detail from the moment the bomb fell and as they struggled to exist through the ensuing weeks, Hersey did something altogether different. He bore witness.

The issue of the magazine sold out at newsstands. The thirty-one-thousand-word article was read over the radio; parts of it were excerpted in newspapers; three million copies of it were sold in book form. It has been in print ever since.

Yet while Hersey, who was thirty-two at the time of publication, and who had covered the war extensively for Time and Life, received accolades, and some criticism, in the aftermath of “Hiroshima,” he remained somehow outside the glare of the attention it generated. Likewise, for all the humanity of the article, its author, who died in 1993, seems scarcely present in it; it seems almost not to have an author. And the man who wrote what has been called the most important work of journalism of the twentieth century, as well as a shelf of best-selling novels and works of nonfiction, seems largely forgotten today.

As it happens, one of John Hersey’s sons, Baird, is my brother-in-law. Through the years, at holiday gatherings, we have chatted about his father. With this anniversary in mind, we had a more purposeful conversation. I asked Baird, who is a musician and composer living in upstate New York, about the man his father was, about his approach to writing “Hiroshima,” and about the enigma of his authorial persona.

“My father had a very strong moral compass,” Baird said. “I think it was because his parents were missionaries. He lived in China, where they were doing Y.M.C.A. mission work, until he was eleven. Even though he wasn’t a religious person—he eventually reacted against being raised in that world—he had a strong sense of right and wrong, and a humility, and that colored his approach to ‘Hiroshima.’ ”

Hersey was on a Navy ship on his way to Japan to report the story when he fell ill and someone gave him books to read, one of which happened to be Thornton Wilder’s “The Bridge of San Luis Rey.” It was a novel that traced the stories of five people who are killed when a bridge collapses. “It struck my father that that would be a good vehicle for presenting the story of the people who were subjected to the atomic bomb,” Baird said. “He told me about getting the idea of using novelistic devices to structure his reporting. He wanted to put faces and names to the story. Prior to that, we had been at war with Japan, and everyone had this opinion of ‘the Japanese.’ He wanted to show their humanity in a way that people in this country could connect to—to convey the enormity of what had happened.”

The structure of “Hiroshima” was one of the things that resonated with readers. Its use of fictional devices, such as building to a suspenseful moment with one character and then switching to another, was radical at the time, and made it a precursor to the New Journalism of the nineteen-sixties and seventies. Hersey himself said that the profundity of the nuclear attack, and his consequent need to try to convey the reality of it to readers, forced him outside of journalistic conventions. With journalism, Hersey once said, the reader is always conscious of “the person who’s writing it and explaining to you what’s taken place.” He said he wanted to have “the reader directly confronted by the characters,” so he tried to write the piece in such a way that, as he put it, “my mediation would, ideally, disappear.”

The disappearing writer was not just a feature of the work itself but, in a sense, of Hersey’s career. “He was quite young when he had his success, but it didn’t go to his head,” Baird told me. “I think he found the acclaim and attention to be hollow.” As a result, the author of the biggest publishing sensation of its time was a virtual stranger to the world of publicity. “He never went on tour. He never wanted to ‘flog his wares,’ as he said. He didn’t go on TV or radio, didn’t give lectures. He only did two interviews in his life. He was a member of the generation that developed the cult of the author—people like Norman Mailer were doing ‘The Dick Cavett Show’—but he didn’t want any part of that.”

Baird’s memories of his father are of a private man, but not a recluse. Hersey had a small circle of close friends, which included Lillian Hellman, William Styron, Ralph Ellison, Jules Feiffer, and Anthony Lewis. He belonged to civic organizations, spoke out against the Vietnam War, and taught writing at Yale. But he was guarded about his work. “He had this theory that you should never talk about a book you were working on,” Baird said. “He felt that writers would lose the energy of their stories by talking about them. So we didn’t even know what he was writing. Then there would be a dinner after he had sent the manuscript to the publisher, and he would share with the family what the book was about.”

Baird was born after the publication of “Hiroshima.” His memories are of his father at work on later books. They lived in Fairfield, Connecticut, and Hersey wrote in a small cottage some distance from the house. “I used to climb a tree, knock on the window, and ask if he could come out. He was very regular in his habits. Every morning he would write, in longhand, double-spaced, so that he could make corrections. In the afternoons he would answer correspondence. He got lots of mail, and there was only one kind of letter he would not answer. If the name was spelled ‘Hershey,’ it went in the trash can.”

Baird doesn’t remember his father making a big deal about any of his work, or his fame. “He was very reserved, which I think he regretted, because he had a loving and warm side,” he said. “If my parents were having a dinner party and I couldn’t sleep, he’d come up and rub my back.”

In a perfect world, fathers exert a firm and wise influence on their children. Perhaps that rarely happens. But Baird told me that his father’s philosophy on work and the world coalesced for him in one conversation they had. Baird was himself about the age his father had been when “Hiroshima” was published. “We were on Martha’s Vineyard, where he always spent his summers. I had built up a body of work as a musician. I had just had a record come out that had gotten some attention but didn’t break out. I was in that phase of my career, trying to figure it out. I guess I had something in me that pulled me toward wanting fame. I wanted to know how he had managed things early in his career. And what he said, essentially, was you can’t look to the outside world to make you whole. That affected me profoundly.”

Hersey’s refusal to flog his wares continues in effect. His daughter, Brook Hersey, a clinical psychologist living in Manhattan, who is his literary executor, told me that when it comes to ancillary projects that people bring to her—movie deals, prospective biographies—“I have tried to make decisions based on what I think he would have wanted, and that was to let his works speak for themselves.” As a result, she said, “I’ve always erred on the side of saying no.”

The slow fade in popular awareness of Hersey is surely in part a result of that, as well as of the simple passage of time. But Hersey’s sensibility, so at odds with today’s, suited its era. The authorial anonymity—the humility—in “Hiroshima” made it the most respectful way to present the people Hersey encountered in a post-nuclear city, and the clearest way to show Americans what they had done.