“I have some hard ‘confessing’ to do—if not in public, at least to Shengold—and myself,” Sacks wrote in his journal, in 1985. By then, he had published four books—“Migraine,” “Awakenings,” “A Leg to Stand On,” and “The Man Who Mistook His Wife for a Hat”—establishing his reputation as “our modern master of the case study,” as the Times put it. He rejected what he called “pallid, abstract knowing,” and pushed medicine to engage more deeply with patients’ interiority and how it interacted with their diseases. Medical schools began creating programs in medical humanities and “narrative medicine,” and a new belief took hold: that an ill person has lost narrative coherence, and that doctors, if they attend to their patients’ private struggles, could help them reconstruct a new story of their lives. At Harvard Medical School, for a time, students were assigned to write a “book” about a patient. Stories of illness written by physicians (and by patients) began proliferating, to the point that the medical sociologist Arthur Frank noted, “ ‘Oliver Sacks’ now designates not only a specific physician author but also a . . . genre—a distinctively recognizable form of storytelling.”

But, in his journal, Sacks wrote that “a sense of hideous criminality remains (psychologically) attached” to his work: he had given his patients “powers (starting with powers of speech) which they do not have.” Some details, he recognized, were “pure fabrications.” He tried to reassure himself that the exaggerations did not come from a shallow place, such as a desire for fame or attention. “The impulse is both ‘purer’—and deeper,” he wrote. “It is not merely or wholly a projection—nor (as I have sometimes, ingeniously-disingenuously, maintained) a mere ‘sensitization’ of what I know so well in myself. But (if you will) a sort of autobiography.” He called it “symbolic ‘exo-graphy.’ ”

[...]

It speaks to the power of the fantasy of the magical healer that readers and publishers accepted Sacks’s stories as literal truth. In a letter to one of his three brothers, Marcus, Sacks enclosed a copy of “The Man Who Mistook His Wife for a Hat,” which was published in 1985, calling it a book of “fairy tales.” He explained that “these odd Narratives—half-report, half-imagined, half-science, half-fable, but with a fidelity of their own—are what I do, basically, to keep MY demons of boredom and loneliness and despair away.” He added that Marcus would likely call them “confabulations”—a phenomenon Sacks explores in a chapter about a patient who could retain memories for only a few seconds and must “make meaning, in a desperate way, continually inventing, throwing bridges of meaning over abysses,” but the “bridges, the patches, for all their brilliance . . . cannot do service for reality.”

[...]

The “most flagrant example” of his distortions, Sacks wrote in his journal, was in one of the last chapters of “Hat,” titled “The Twins,” about twenty-six-year-old twins with autism who had been institutionalized since they were seven. They spend their days reciting numbers, which they “savored, shared” while “closeted in their numerical communion.” Sacks lingers near them, jotting down the numbers, and eventually realizes that they are all prime. As a child, Sacks used to spend hours alone, trying to come up with a formula for prime numbers, but, he wrote, “I never found any Law or Pattern for them—and this gave me an intense feeling of Terror, Pleasure, and—Mystery.” Delighted by the twins’ pastime, Sacks comes to the ward with a book of prime numbers which he’d loved as a child. After offering his own prime number, “they drew apart slightly, making room for me, a new number playmate, a third in their world.” Having apparently uncovered the impossible algorithm that Sacks had once wished for, the twins continue sharing primes until they’re exchanging ones with twenty digits. The scene reads like a kind of dream: he has discovered that human intimacy has a decipherable structure, and identified a hidden pattern that will allow him to finally join in.

Before Sacks met them, the twins had been extensively studied because of their capacity to determine the day of the week on which any date in the calendar fell. In the sixties, two papers in the American Journal of Psychiatry provided detailed accounts of the extent of their abilities. Neither paper mentioned a gift for prime numbers or math. When Sacks wrote Alexander Luria, a Russian neuropsychologist, about his work with the twins, in 1973, he also did not mention any special mathematical skills.

[...]

After “Hat,” Sacks’s relationship with his subjects became more mediated. Most of them were not his patients; many wrote to him after reading his work, recognizing themselves in his books. There was a different power dynamic, because these people already believed that they had stories to tell. Perhaps the guilt over liberties he had taken in “Hat” caused him to curb the impulse to exaggerate. His expressions of remorse over “making up, ‘enhancing,’ etc,” which had appeared in his journals throughout the seventies and eighties, stopped. In his case studies, he used fewer and shorter quotes. His patients were far more likely to say ordinary, banal things, and they rarely quoted literature. They still had secret gifts, but they weren’t redeemed by them; they were just trying to cope.

[...]

Kate Edgar, who worked for Sacks for three decades, had two brothers who were gay, and for years she had advocated for gay civil rights, organizing Pride marches for her son’s school. She intentionally found an office for Sacks in the West Village so that he would be surrounded by gay men living openly and could see how normal it had become. She tended to hire gay assistants for him, for the same reason. “So I was sort of plotting on that level for some years,” she told me.