‘Insomniac City: New York, Oliver, and Me,’ by Bill Hayes

One afternoon at a cafe in New York’s West Village in 2005, the famed neurologist Oliver Sacks made the only prediction I heard him make that didn’t come true.

I had met the author of books like “Awakenings” and “The Man Who Mistook His Wife for a Hat” a couple of years earlier while writing a profile of him for Wired magazine. I greatly admired Sacks’ books for their humane portrayals of people with challenging neurological conditions like autism, agnosia and Tourette’s syndrome. I also found that I liked the flamboyantly eccentric and ebullient man — who showed up at our first meeting in a bathing suit, fresh from his daily swim — who had written them. In the course of my research, however, I figured out that the man who had helped millions of readers feel comfortable with their own idiosyncrasies had a painful secret: He was a closeted gay man who was hiding behind widespread media reports that he was “asexual.” (In the film adaptation of “Awakenings,” in which Sacks was portrayed with uncanny sensitivity by the late Robin Williams, he was furnished with a fictitious heterosexual love interest.)

Sacks confided to me that his shyness about his sexual orientation was rooted in his mother’s religious orthodoxy and cruel response to him when he came out to her as a young man: “I wish you had never been born.” He had become fascinated by the seemingly carefree and open relationship I had with my future husband, a science teacher named Keith. I was flattered when Sacks informed me that he had been dreaming about us, which I took as an indication that we symbolized something important for him — the road not taken, perhaps.

“How about you, Oliver?” I asked him. “Have you ever been in love?”

A disconsolate look swept over his face. Sacks told me about a brief affair he’d had three decades earlier, with a swimmer he met on Hampstead Heath in London. “Little did I know, that would be my last chance at love,” he sighed. “It’s too late for me.”

Now a new book called “Insomniac City,” by writer and photographer Bill Hayes, makes clear that the good doctor’s dour self-diagnosis was premature. A memoir of Hayes’ surpassingly tender and exuberant romance with Sacks in his last seven years of life, it is also a book about the necessity of self-reinvention.

The love story at its heart is bracketed by loss. The opening sections describe the sudden, wrenching death of Hayes’ lover, Steve, in San Francisco; and the book closes with a moving account of Sacks’ death of metastatic cancer at home in New York, with Hayes at his side, at age 82. Between these two deep wells of grief, Hayes discovers an inexhaustible fountain of renewal by plunging into the unknown. After moving to New York to start a new life, Hayes impulsively buys a camera, becomes a street photographer and adds a jaunty “y” to his first name. Then, through an exchange of letters (Sacks’ preferred medium of social networking), he meets the neurologist he calls “the most unusual man” he ever knew. Though Hayes was 30 years younger than Sacks, he was instantly smitten. By falling in love with Hayes, Sacks is also renewed and reinvented — transformed from a habitually solitary man who “didn’t know how to share,” as Hayes puts it, to an endearingly geeky romantic who dons a pair of swimming goggles to pop open a bottle of Champagne for the first time, gradually loses his fear of holding hands with his boyfriend in public, and asks Hayes, “Is that what kissing is, or is that something you’ve invented?”

Sacks was characteristically self-effacing, but he was always aware that his writing had earned him a place in history. One of the first pieces of advice that he gives to his handsome young lover is to start keeping a journal. The excerpts from this journal that appear in “Insomniac City” capture the neurologist’s exquisitely memorable way of saying things, which made one wish that one was always carrying a tape recorder in his presence. “You create the need you fill, the hunger you sate,” Sacks tells Hayes at one point, “like Jesus. And Kierkegaard. And smoked trout.” As they lie in bed together, Sacks observes, “I like having a confusion of agency, your hand on top of mine, unsure where my body ends and yours begins” — like a teenager marveling at the primordial mystery of sex in the vocabulary of an eminent author.

Much of the loveliest writing in the book, however, belongs to Hayes alone, whose previous book, “The Anatomist” (a poetic exploration of the lives of Henry Gray and Henry Vandyke Carter, author and illustrator of the classic medical textbook “Gray’s Anatomy”), prompted Sacks’ initial letter. Ultimately, what makes a memoir worth reading is its acuity of observation, and Hayes is a 21st century flaneur — like Whitman or Baudelaire with a digital camera and an insatiable appetite for the serendipitous connections that thrive in liminal places like the subway. Recounting a series of candid exchanges with cab drivers, Hayes reflects that the plastic screen between driver and passenger is “not unlike that in a confessional booth.” Noting that his own way of seeing the world is converging with Sacks’, he says, “We are like two dogs rubbing our scents onto one another.” Only rarely do Hayes’ paeans to his newly adopted metropolis veer toward the precious, as when he muses, “We are closer to the sun in New York.”

Like Patti Smith’s haunting “M Train,” Hayes’ book weaves seemingly disparate threads of memory into a kind of sanctuary — a secret place where one can shake off the treasured relics of past lives and prepare to be reborn anew.

Insomniac City

New York, Oliver, and Me

By Bill Hayes

(Bloomsbury; 291 pages; $27)