Dr. Sacks depicted such people not as scientific curiosities but as individuals who become as real to us as characters by Chekhov (another doctor who wrote with uncommon empathy and insight). He was concerned with the impact that his patients’ neurological disorders had on their day-to-day routines, their relationships and their inner lives. His case studies became literary narratives as dramatic, richly detailed and compelling as those by Freud and Luria — stories that underscored not the marginality of his patients’ experiences, but their part in the shared human endeavor and the flux and contingencies of life.

Those case studies captured the emotional and metaphysical, as well as physiological, dimensions of his patients’ conditions. While they tracked the costs and isolation these individuals often endured, they also emphasized people’s resilience — their ability to adapt to their “deficits,” enabling them to hold onto a sense of identity and agency. Some even find that their conditions spur them to startling creative achievement.

In fact, Dr. Sacks wrote in “An Anthropologist on Mars,” that illnesses and disorders “can play a paradoxical role in bringing out latent powers, developments, evolutions, forms of life that might never be seen or even be imaginable in their absence.” A young woman with a low I.Q. learns to sing arias in more than 30 languages, and a Canadian physician with Tourette’s syndrome learns to perform long, complicated surgical procedures without a single tic or twitch. Some scholars believe, Dr. Sacks once wrote, that Dostoyevsky and van Gogh may have had temporal lobe epilepsy, that Bartok and Wittgenstein may have been autistic, and that Mozart and Samuel Johnson could have had Tourette’s syndrome.

In his later books, Dr. Sacks increasingly turned to chronicling his own life — from his deep love of chemistry as a boy in “Uncle Tungsten,” to his experiments with L.S.D. and amphetamines in “Hallucinations,” to his coming of age as a young man and as a doctor in “On the Move.” It was a life as eclectic and adventurous as his intellectual pursuits, taking him from medical school in England to a stint as a forest firefighter in British Columbia to medical residencies and fellowship work in San Francisco and Los Angeles. He held a weight-lifting record in California, and on weekends, sometimes drove hundreds of miles on his motorcycle, from California to Las Vegas or the Grand Canyon.