I was in a master’s program for science journalism at Columbia University, and Sacks—a neurologist and writer who told incredible case histories of his patients in numerous bestselling books—made an annual visit to our class, a result of being friends with my professor, Jonathan Weiner. His appearance was scheduled toward the end of the semester to “save the best for last,” as Weiner recently told me. But in August 2015, the very beginning of that school year, Sacks died from cancer at 82 years old.

Next week, a new documentary directed by Ric Burns called Oliver Sacks: His Own Life will be shown at the New York Film Festival , after premiering at Colorado's Telluride Film Festival in August. The movie includes interviews with friends and family, as well as physicians and scientists like Atul Gawande, Eric Kandel, Anil Seth, and Christoph Koch.

His tone was playful, compassionate, but most of all, completely earnest. Since he died, I have snatched up any posthumous work with his byline, and I’m not the only person eager to keep devouring his writing. Interest in Sacks has been increasing, said Kate Edgar, Sacks’s longtime editor, friend, and executive director of the Oliver Sacks Foundation . More than four years later, his partner of six years, writer and photographer Bill Hayes , still gets letters and messages from people all over the world who loved Sacks.

I did not know it was possible to miss someone you had never met until I lost my chance to cross paths with Sacks. As a teenager, I had a worn copy of his 1985 book, The Man Who Mistook His Wife for A Hat, and remember reading it for the first time with a feeling of delight and surprise. The stories of the patients with amnesia and those who couldn't recognize faces captivated me, but so did the narrator. Sacks was the first author I had read who exuded a kind of joy and wonder at individuals with neural differences. I learned from him that there’s a joy in being an outsider. (Sacks never became an American citizen, retaining his British passport, and would say, “I kind of like my alien status.”) Sacks was a champion for neurodiversity before people were even using the phrase.

Around Christmas in 2014, Sacks finished his autobiography, On the Move, and a few weeks later received a terminal prognosis from his doctor. When he told people about the cancer, friends and family started to routinely visit him at his West Village apartment. “He didn’t want to just dwell on his illness, and he was really proud of the book, so he would read chapters or passages from On the Move,” Hayes said. Sacks' distinct boyish, English cadence was such a delight that one night, a friend said his performances should be captured on video. Sacks agreed.

And yet despite his genius, he openly talked about how his peculiarities and niche interests could make him feel odd, like an outsider. He also had one of the conditions he wrote about in others, face blindness , writing in The New Yorker that it could make for awkward situations—like not recognizing the psychiatrist he had seen for several years, or sometimes not recognizing himself: “On several occasions I have apologized for almost bumping into a large bearded man, only to realize that the large bearded man was myself in a mirror," he wrote.

In that way, he was like a figure from another time: He wrote completely by hand with a fountain pen, and was the kind of person whose topics of conversation, during, say, a bike ride with his friend Orrin Devinsky, might meander from the origin of the name of dandelions to the toxicity of eating fireflies—Sacks made Devinsky promise to never eat more than two fireflies (presumably one would be okay).

Any time Sacks spoke, on the radio or through his writing, he revealed a mind that was an expert in many topics, including literature, philosophy, biology, and history. (He was not an expert on culture; Hayes has written that Sacks knew nothing about pop culture after 1955, and when Michael Jackson died, Sacks said, "What is Michael Jackson?”)

The roughly two-hour long movie is excellent, but I knew deep down that it could have been eight hours, shot on a wobbly iPhone, with a finger partially covering the lens, and I would have been riveted simply because Sacks was in it. And so I watched with a larger, singular question: Why is it that I— we—can't let go of Oliver Sacks?

Sacks has been featured in films before, but this is the first documentary about his entire life. It covers his writing and medical career, but also his traumatic early-life experiences, rejections from the scientific community, his struggles with his homosexuality, and his preternatural ability for compassion and empathy towards people with a wide range of neurological disorders.

Once you know about Sacks' whole life, the striking thing about him is not that he is universally beloved, but that he spent much of his life not beloved. In the film, you learn about the physical and emotional abuse he suffered at boarding school, his romantic failures (and 35-year-long period of celibacy), his rebuffs from the scientific community, and his failed career as a research scientist.

“Here’s a man, 81 years old, who had just finished, but not yet published, a remarkably frank memoir in which he was grappling for the first time with things he'd never talked about publicly outside of a small circle of people,” Burns said. “It’s an extraordinary moment where somebody, at one minute to midnight, wants to double down on his exploration of what life means. What does it mean? What are we doing here?”

“What I love about the film is that it captures him at that moment,” Hayes said. “He just got this terminal prognosis but he's still full of so much vigor and curiosity." In his memoir, Sacks had revealed details about his life that had not been shared before, and did so in the film too.

Burns—the documentary filmmaker known for his multiple series on PBS, and collaborations with his brother, Ken—got a call from Edgar in January 2015 telling him that Sacks was dying. “There was a development period for the film that was approximately one second,” Burns said. Within a few weeks, Burns and his crew were at Sacks’ apartment, around the time his New York Times essay informed the world of his cancer diagnosis.

Sacks’ writing about autism revealed an inner world that most assumed didn't exist. “When Greta Thunberg described her Asperger's as being like a super power, I thought, that is so Oliver Sacks,” Hayes said.

Yet it is partly because of how much of an outsider he felt he was—on so many levels—that he was able to connect to patients with all kinds of disorders and conditions. “He wasn’t as frightened or appalled by people who were in extreme situations, because it didn't seem that extreme to him,” Burns said. Sacks loved to “discover potential in people who aren’t thought to have any,” as he put it in a 1986 interview .

“It’s a strength of the film that one can watch it and think, 'God he was such a fuck up,'” Hayes said. “There are things left out of the film because it had to be under two hours—even more disasters.” Edgar said his big break wasn't until The Man Who Mistook His Wife for a Hat. He was 52.

His mother said that he was an “abomination" when he told her he was gay. Sacks spent a significant period addicted to amphetamines. When he began writing, his books were not always well received; one critic wrote that Sacks was a “doctor who mistook his patients for a literary career.” By the time he was in his mid-40s, he’d been fired from nearly every job he had. In the film, writer and doctor Atul Gawande marveled that, in parts of his life, Sacks could be viewed as a “supreme fuck up.”

His subjects with Tourette’s Syndrome said that Sacks described their condition not as a deficit, but as an excess—and it helped them shift their own perspectives. “That is exactly how Oliver saw his patients,” Hayes said. “Even patients who were severely brain-damaged, who really had some serious physical developmental problems, he was amazed at how they adapted to their condition."

Sacks wrote about such a wide variety of topics—autism, Tourette's, deafness, dementia, amnesia, Parkinson's—that his work could become a kind of mirror for so many to see themselves in. Hayes told me that one evening at a party, a young woman said she had come to know Sacks through Hallucinations, a book in which he chronicled his drug use. It was meaningful for her to know that Sacks had experimented with drugs, been addicted to amphetamines, and then emerged to have a beautiful life. “She said, ‘I was a heroin addict for three or four years," Hayes said. "It was a very dark side of my life. Reading Dr. Sacks' book made me feel less ashamed.’”

Instead of having Sacks speak to our class at Columbia, we watched a YouTube video of him in his home office, where he showed off a collection of elements from the periodic table, and explained how he acquired elements with the atomic numbers that matched his age. In the clip, he was 77, so he presented iridium, element 77—the second densest metal, after osmium. (In an essay in the New York Times from two years later, he wrote: "At 11, I could say 'I am sodium' (Element 11), and now at 79, I am gold.")

This week, I saw that slab of iridium in person, at Sacks' old apartment where Hayes now lives. The square, silver hunk was resting on a bookshelf that held many other of Sacks' keepsakes: books from childhood, other metals and minerals, fossilized ferns.