Shortly before I moved to New York from Los Angeles (my heart’s true home) in 1981, to take up a new position as staff-writer at the New Yorker (following their serendipitous purchase of a long piece of mine on the California artist Robert Irwin), I’d begun corresponding with the neurologist Oliver Sacks, then himself living on City Island, just off the Bronx. His remarkable masterpiece Awakenings—about a group of post-encephalytic Parkinsonian patients, who’d been entrammeled in a seemingly vegetative stupor for decades following the sudden onset of their disease and were being warehoused at Beth Abraham, a home for the incurable, likewise in the Bronx; his administration to them of the new “wonder-drug” L-Dopa, and the drama that thereupon ensued—had been published almost a decade earlier, to virtually no acclaim (except for some great reviews by the likes of W.H. Auden and Frank Kermode) and to widespread dismissal on the part of a medical profession scandalized by its reliance on allegedly superannuated nineteenth century style case studies (“Merely anecdotal! Where are the double-blind controls, the peer-reviewed processes?” etc.). I’d happened to have read it, been thoroughly bowled over, and a tentative correspondence had ensued.

For his own part, Oliver was living a virtual recluse, except for his ongoing clinical rounds at local nursing homes and state hospitals, himself entrammeled in an at that point five-year-long writer’s block regarding his next book, one attempting to recount an existential neurological crisis of his own, brought on by the fact that shortly after the publication (and initial failure) of Awakenings, he’d heedlessly launched out on a solitary mountain hike above a Norwegian fjord, gotten into some sort of run-in with a bull, come crashing down the mountainside, badly mangling his leg and almost dying. During his subsequent recuperation, he experienced a radical bodily dysphoria, in which his injured leg no longer seemed his own—and his attempts since to evoke and analyze that crisis had him thoroughly bollixed and stymied.

I had just turned twenty-nine and he was forty-eight when we first met out there on City Island, but I quickly realized that he would make a wonderful subject for one of those multi-part profiles the magazine was famous for in those days, and across the next four years, I took on the role of a sort of beanpole Sancho to his capacious Quixote, traipsing about with him on his various rounds and travels, chronicling his in those days floridly neurotic ramblings, indeed, filling up over fifteen notebooks full of them, interviewing his friends and patients and earlier associates, and off to the side, trying to help him through that epic blockage, which, curiously,...