British neurologist Oliver Sacks has died at the age of 82, it has been confirmed.
The acclaimed author, whose book Awakenings inspired an Oscar nominated film of the same name, reportedly died of cancer at his home in New York.
In February he wrote about his illness - and being "face to face with dying".
His publicist Jacqui Graham paid tribute to Dr Sacks, saying he was "unlike anybody I have ever met", while JK Rowling said he was "inspirational".
Dr Sacks was best known for his writing, including his book Awakenings - his account of how he brought a group of patients "back to life" after they spent years in "frozen states" after an illness.
The film version, which starred Robert De Niro and Robin Williams, was nominated for three Academy Awards in 1991, including best picture.
Dr Sacks, who was born in London but had lived in New York since 1965, was also the author of several other books about unusual medical conditions, including The Man Who Mistook His Wife For A Hat and The Island Of The Colorblind.
He was awarded several honorary degrees recognising his contribution to science and literature, as well as a CBE in 2008 in the Queen's Birthday Honours.
Mrs Graham told the BBC Dr Sacks was "unlike anybody else I've ever met".
She said she received an email from his long-time PA saying the neurologist had "a very good death, in the same way that he'd had a very good life".
Mrs Graham said: "He died surrounded by the things he loved and the people he loved, very peacefully, after an illness he had known about since January this year. He taught us a great deal, right up until the very end.
"He always taught us what it was to be human, and he taught us what it is to die."
Paying tribute to Dr Sacks, she added: "To say he was unique is for once in the world true.
"He was completely himself - eccentric, but in a marvellous way. He was just completely full of love for life and very impish, and he was childish in the very best sense."
Other tributes to the author have been paid on Twitter, including by the author JK Rowling, who called him "great, humane and inspirational".
Biologist Richard Dawkins tweeted: "I met Oliver Sacks only twice, but greatly admired him. Sad to hear of his death."
Dr Sacks earned a medical degree at Queen's College, Oxford University, and later began working as a consulting neurologist for Beth Abraham Hospital, in the Bronx, New York, in 1966.
While there he encountered patients who had spent decades in frozen states, unable to initiate movement.
He recognised the patients as survivors of a pandemic of sleepy sickness that had swept the world from 1916 to 1927, and treated them with a then-experimental drug, L-dopa, which enabled them to regain consciousness.
They became the subjects of Awakenings and also later inspired a play by Harold Pinter - A Kind of Alaska.
In The Man Who Mistook His Wife for a Hat and An Anthropologist on Mars he described patients struggling to live with conditions ranging from Tourette's syndrome to autism, epilepsy, phantom limb syndrome, schizophrenia, and Alzheimer's.
He also investigated the world of deaf people and sign language in Seeing Voices, and a rare community of colour-blind people in The Island of the Colorblind.
More recently, he served as a professor of neurology and psychiatry at Columbia University Medical Centre from 2007 to 2012.
He was also a professor of neurology at the NYU School of Medicine.