Oliver Sacks was an honorary member of that exclusive club I like to think of as the Wise English Prophets.

His generation included the medico and theatre director Jonathan Miller, the art historian Sir Kenneth Clark, the mathematician Jacob Bronowski and the naturalist David Attenborough.

Later members are the historians Simon Schama and Bettany Hughes, and the physicist Brian Cox.

Sorry, this audio has expired Listen to Michael Cathcart's interview with Bill Hayes:

One after another, they have addressed us on TV with their takes on civilisation and the triumph of reason.

Whatever their discipline, they are all players in the same epic drama — they speak of the human animal facing the wonder of the cosmos.

All believe that this cosmos is knowable — that our silent awe is expanded by the even greater miracle of human understanding.

The cosmos that fed the childlike wonder of Sacks was the human brain.

He was a neurologist who treated people whose brains malfunctioned in usual and sometimes distressing ways.

Sacks stepped into the spotlight in 1973 with a book called Awakenings, in which he explained how he had "woken up" a group of patients who had been sent into a decades-long sleep by a malfunction in their nervous systems.

But, like thousands of people throughout the Anglosphere, I discovered him through his bestselling book The Man Who Mistook His Wife for a Hat (1985), in which Sacks shared a series of astonishing stories about his patients and their aberrant relationships with the wider world.

The muddled man of the title was an extremely engaging music teacher named Dr P.

Oliver Sacks' partner Bill Hayes took a series of intimate portraits in their New York apartment. ( Supplied: Bill Hayes )

The odd thing about Dr P was that he was unable to distinguish faces.

In fact, when Sacks called on the man at home, Dr P made a move to shake hands with his own grandfather clock.

Strangely, Dr P did not seem to be worried by his peculiar relationship with the rest of the world. It was his friends who kept telling him that something was wrong.

As Sacks explained, Dr P suffered from a condition known as face blindness — a condition Sacks analysed for his lay readers with his own genial brand of erudition.

I never quite understood the biochemistry of it all, but I felt as though I did. That feeling was comforting — a defence against what has always seemed to me to be the perilous fragility of the human brain.

What we didn't know back then is that Sacks himself suffered from the same kind of face blindness.

This man, who spoke with such authority about the most intimate functionings of the human animal, lived in a world of unrecognisable faces. A world of strangers.

His world was even more idiosyncratic than that. He never owned a computer. He never sent an email or a text. His address book contained just six names.

Oliver Sacks' genial brand of erudition allowed readers to understand complex neurological phenomena. ( Getty Images: James Leynse )

Strangest of all, throughout all the years of his celebrity, Sacks lived alone. For 35 years, he had no partner and, apparently, no interest in sex.

In fact, Sacks was gay. But he had grown up at a time when homosexuality was illegal in Britain — and in a traditional Jewish community where homosexuals were regarded as abominations against God and nature.

In 2009, at the age of 75, Sacks surprised himself. He met a man named William Hayes and fell in love.

Bill Hayes was just 48 — and was living with grief. Not long before, his partner Steve had died of a heart attack, lying in bed beside him.

He'd moved to New York in search of a new beginning, and had found an unexpected romance with a writer he admired — Sacks.

Hayes tells the story of their love in a tender and generous memoir called Insomniac City.

Oliver Sacks died in August, 2015. ( Supplied: Bill Hayes )

They lived in separate apartments in the same West Village building: Sacks's apartment was their centre — a kind of time capsule in which they created a world of their own.

Sacks wrote three full-length books during their time together. He also took piano lessons, swam and embraced life in New York.

As Hayes tells the story, Sacks lived in a state of almost childlike wonder — a wonder which increased as Hayes unfolded the modern world to him.

When they tongue-kissed for the first time, Hayes tells us, Sacks had a look of utter surprise on his face.

"With his eyes still closed, he asked, 'Is that what kissing is? Or is it something you have invented yourself?'

The aging Sacks was assailed by various health problems — a broken hip, a knee replacement, bad eyesight and poor hearing, and in January 2015 he was diagnosed with terminal cancer.

Hayes cared for him right to the end. Insomniac City is a tale of love, both for Sacks and for New York, the city which (famously) never sleeps.

When Hayes is not telling us about life with Sacks, he is out on the streets.

He photographs New York and New Yorkers with such intimacy that I ended up grieving for the New York life I never had.

Best of all — the book introduced me to another Wise Prophet: Hayes, a man with a gift for a story, a talent for tenderness, and an eye for humanity at its most vulnerable.

Bill Hayes will appear at the Sydney Writers' Festival in May 2017.