The neurosurgeon Henry Marsh, who first turned to writing in his 60s, has won himself a place on the Guardian first book award shortlist for his acclaimed debut dissecting his life as a brain surgeon.

The 64-year-old is the oldest author on a shortlist that also includes two collections of short stories, a novel, and an investigation into modern China. Hailed by the novelist Ian McEwan as a memoir in which “neurosurgery has met its Boswell”, Do No Harm is Marsh’s attempt to show what life is really like for a brain surgeon. Writing in Saturday’s Guardian Review, Marsh explains how the stories try to capture “the fierce joy of operating and the difficulty of balancing compassion and professional detachment; they show how we doctors are as human as our patients”.

The memoir opens with a confession. “I often have to cut into the brain and it is something I hate doing … I cut into it with a small scalpel and make a hole through which I push with a fine sucker – as the brain has the consistency of jelly a sucker is the brain surgeon’s principal tool … The idea that my sucker is moving through thought itself, through emotion and reason, that memories, dreams and reflections should consist of jelly, is simply too strange to understand.”

Judge and author Mary Beard said she had been “stunned” by the quality of books in the running for the award – longlisted titles which failed to make the shortlist include Super Furry Animals singer Gruff Rhys’s travelogue American Interior, and Marion Coutts’s memoir of her husband’s terminal brain tumour, The Iceberg.

“It’s great to have a prize for first books, but to be honest it is hard to believe that those on the shortlist really are first books. They are so accomplished, clever, assured – and, of course, enjoyable, moving and challenging reads,” said Beard.

“It also reminds us that first books are not just written by the young,” she added. “I don’t want to be ageist, but I think our oldest author is 64-year-old Henry Marsh, whose Do No Harm is a tremendous combination of freshness of voice with a lifetime of experience.”

Do No Harm sits alongside one other piece of non-fiction on the shortlist: American journalist Evan Osnos’s Age of Ambition, in which the author follows the lives of a diverse selection of people living in China, telling the stories of everyone from a barber who made spectacular fortune in Macau’s gambling dens, to an army captain who swam from Taiwan to China. “At a time when China and the west can seem to be moving farther apart, I have tried to record the fact that, on the ground, we have never shared more sensibilities and experience,” writes Osnos in Review.

The Guardian prize, worth £10,000, is for a first title in any genre, and has been won by Zadie Smith’s debut novel White Teeth, Siddhartha Mukherjee’s “biography” of cancer The Emperor of All Maladies and Robert Macfarlane’s exploration of mankind’s response to mountains, Mountains of the Mind. This year, Australian Fiona McFarlane is shortlisted for her novel The Night Guest, a psychological thriller in which a widow living in isolation in New South Wales and starting to suffer from dementia sees a carer inveigle her way into her life.

“Her world is blurring, and she is both frightened of and fascinated by it. I’ve seen dementia do its painful work on people I love, and I wanted to imagine it from the inside,” writes McFarlane in Review. “I wanted, too, to write a character who resists our cultural expectations of older women. Ruth is kind and sensible but not floral and insipid. She swears and has sex but isn’t eccentrically feisty.”

Two very different short-story collections complete the shortlist: Irish author Colin Barrett’s Young Skins, set among the inhabitants of his fictional west-of-Ireland town of Glanbeigh, and Things to Make and Break by May-Lan Tan, who grew up in Hong Kong and is now based in London. Tan’s debut was voted onto the longlist by Guardian readers, but her dark stories also won her the acclaim of the prize’s judges.

“The list goes from Colin Barrett, an Irish short-story writer who has been hailed as the new ‘young genius’ after winning the Frank O’Connor short-story award, to a 64-year-old neurosurgeon who has already made it to the top of his field, and who makes highly technical subject matter absolutely gripping and accessible,” said Guardian Review editor Lisa Allardice. “It also looks at the world, ranging from rural Ireland to China and its economic boom.”

Allardice said she had been struck, reading the submissions for the prize, at this year’s relative lack of autobiographical novels. “In previous years, one of the things I’ve noticed is the sheer number of semi-clad memoirs, and the high preponderance of child narrators,” she said. “This year, if there has been a trend, it is of very good novels about older people, reflecting growing concerns about Alzheimer’s and dementia.” Two of the longlisted titles, McFarlane’s novel and Matthew Thomas’s We Are Not Ourselves, deal with the subject.

Allardice and Beard are joined on the judges’ panel by the Booker prize-winning novelist Anne Enright, MP Tristram Hunt and psychotherapist Josh Cohen. The winner of the award will be announced on 26 November 2014.

The 2014 shortlist for the Guardian first book award
Age of Ambition by Evan Osnos (Read the Guardian’s review)
Do No Harm by Henry Marsh (Read the Observer’s review)
The Night Guest by Fiona McFarlane (Read the Guardian’s review)

Things to Make and Break by May-Lan Tan (Read the Guardian’s review)
Young Skins by Colin Barrett (Read the Guardian’s review)