The avalanche of acclaim that greeted Death of a Salesman in 1949 turned Art Miller into Arthur Miller and invested him with almost oracular prestige. “He lived the life of an established god, and liked it,” Elia Kazan wrote, who, as the director of “Salesman” and All My Sons, was both the engineer and the witness of Miller’s elevation. The plays may have been a theatrical liberation, but, personally, Miller, who had married just out of university, was “rigid with inhibition,” according to Kazan. Success opened Miller’s eyes and awoke his appetites. “He had a roving eye but a bleeding heart,” Kazan observed.

What made Miller an object of desire to the public also made him an object of envy at home. He was caught in the crosshairs of adoration and hate. “I am wearing out the threshold of the doghouse,” he wrote to Kazan in 1950, about the judgmental froideur of his wife, Mary Slattery Miller, the mother of his first two children and the bulwark of his apprentice years. “He was longing for something nameless, a condition I recognized in my own life,” Kazan said. “What did he want? It wasn’t complicated. Call it fun, a new experience, ease of mind and heart, relief from criticism, happiness. His life, he told me, seemed to be all conflict and tension, thwarted desires, stymied impulses, bewildering and unexpressed conflicts.” And then he met Marilyn Monroe.

Of all the requirements of biography—knowledge, style, interpretation, perseverance—perhaps the most underrated is luck. Mine was a four-page single-spaced letter Miller typed to his parents and circulated to his elder brother, Kermit, and his younger sister, Joan, at the time of his divorce in 1956, elaborating on his dead marriage and on his courtship of Monroe. (The letter was provided by Miller’s nephew Ross Miller, himself a university professor, who knew Miller well enough to speak at his funeral.) In it, Miller said of Mary, “For me she was a vindictive, punishing woman. I was not overstating things when I told you that had I not made this break I would have sought another way than writing to make a living. I cannot write when I’m full of hate and surrounded by hate.”

When they were first introduced, in Hollywood, Monroe was Kazan’s squeeze; she was also his intended date to the producer’s party being thrown in Miller’s honor. But, due to a business meeting, Miller was Kazan’s courtly stand-in. When Kazan finally arrived at the party, he could see “the lovely light of desire in their eyes.” “I was never alone with her for five minutes—although Mary never believed this and is incapable of believing it,” Miller wrote about their first encounter to his parents on May 9, 1956.

“He lived the life of an established god, and liked it.”

“She was unknown then, having appeared in a few pictures but not a star. I had certainly never heard of her. To everyone else, apparently, she was the sexy dame. To me she had a face bathed in tears, was scared to death, and could barely talk above a whisper. For reasons I have never understood I told her what I thought—which was that she would be a great star.” He added, “I saw her three or four times over a period of three days, but never alone.” That was it. Monroe kept a photo of Miller at her bedside; he returned to New York to work at his vexed marriage, but he kept Monroe’s paradoxical radiance forever in mind. “She wrote me twice and I replied, and said that she had to go her own way,” Miller wrote to his parents.

By the time they re-met, in April 1955 in New York, where Monroe had moved to study acting at the Actors Studio, she had married and divorced Joe DiMaggio, become an international star, and was in the process of setting up her own production company. Their affair was sandwiched between Monroe’s acting lessons; her five-times-a-week psychoanalysis; business plans for her company’s first project, The Prince and the Showgirl; renegotiations for her contract with Twentieth Century Fox; and preparing for her upcoming film Bus Stop.

“She has more courage, more intimate decency, more sensitivity and love for humanity than anyone I ever knew in my life,” he told his parents, announcing his love, adding, “We have had little continuous time together, really, and, while I want to marry her some day I can’t say now when it will be.” Fifty-four days later, on June 29,1956, Miller and Monroe were married. It was a rookie mistake. As the letter reveals, Miller hardly knew his bride.

Although the media ballyhooed their differences—The Egghead and the Hourglass, The Genius and the Goddess, The Great American Brain and the Great American Body—both of them inhabited climates of loss; each saw salvation in the other. To Miller, who had lived so long in an emotional desert, Monroe was a kind of oasis. “I have come alive at last and I mean to keep myself that way,” he told his parents. To Monroe, who was rudderless and “went for the drug of reassurance,” as Kazan put it, Miller was a contact high—some kind of anchor, a father figure (she nicknamed him “Papa”), a teacher, and a talisman of her transformation and worth. “If I were nothing but a dumb blonde, he wouldn’t have married me,” Monroe said.

In the ardor of their whirlwind romance, Miller had been ravished by Monroe’s practiced and compelling gaiety. “He saw me as so beautiful and innocent among the Hollywood wolves that I tried to be like that,” she said. But it was only when he accompanied Monroe to London and saw her at work on the crisis-torn set of The Prince and the Showgirl that Miller encountered for the first time the deep, anarchic currents of what she called her “terror beyond fear.”

“She has more courage, more intimate decency, more sensitivity and love for humanity than anyone I ever knew in my life.”

“When the monster showed, Arthur couldn’t believe it,” Monroe said. Before Miller’s eyes, her buoyancy and her luster vanished, replaced by the spectacle of a sleep-starved, abusive, drugged collapse. “She was like a smashed vase. It is a beautiful thing when it is intact, but the broken pieces are murderous and they could cut,” Miller said.

To his notebook, which either unconsciously or by design he left open, he admitted the sour feelings he had to repress in order to get a hearing with his wife. “It was something about how disappointed he was with me,” Monroe tearfully told her acting coach Lee Strasberg. “How he thought I was some kind of angel but now he guessed he was wrong. That his first wife had let him down, but I had done something worse.”

“I’d say out of five we had two good years,” Miller said. “But her addiction to pills and drugs defeated me. If there was a key to her despair I never found it.” The bond of trust between them had been broken within those first four months of their celebrated union. Monroe’s madness and his own stupidity were traumatizing and indigestible.

In his subsequent work After the Fall, The Ride Down Mt. Morgan, Everybody Wins, and Finishing the Picture (his last play, in the year before he died), Miller was still trying to make sense of it. His idealizing letter to his parents is a rare demonstration in private of Miller’s emotional naïveté; something he could never quite admit in public. The closest he came was in a cut line from After the Fall: “Innocence kills.”

John Lahr is a Columnist for AIR MAIL and the first critic to win a Tony Award, for co-authoring Elaine Stritch at Liberty. Arthur Miller: American Witness is out on November 1 from Yale University Press