Oliver Sacks was a British Neurologist. He was remarkable for his empathy and caring as well as his gift for using the English language so well as rare as that would seem, nowadays. He took care of patients in a Home for the elderly, as well as being a renowned author.
While the melanoma had spread to his liver, he never lost the qualities which endeared him to many. He wrote many essays and books about his patients, the brain and how it works, and the human condition.
Many remember one in particular, “Awakenings”.
He tackled many illnesses and conditions. Among them, autism, Tourette's Syndrome, and Parkinson's Disease. Other books explored deafness, colorblindness, migraines, hallucinations, and other phenomena.
In the TED talk linked, he spoke about hallucinations…you might find it as captivating as I did.