It’s an irony of our secular age that the more we fear death, the more enticing we find it. The past few years have seen a slew of bestsellers on the subject — Atul Gawande’s Being Mortal, Julian Barnes’s Nothing to be Frightened Of, Paul Kalanithi’s When Breath Becomes Air, Henry Marsh’s Do No Harm (a title taken from the Hippocratic Oath —an oath no doctor actually swears). To this crowded field Robert McCrum brings a book both intensely personal — he reflects not only on his mortality but on the death of his marriage — and coolly objective. It’s proof, yet again, that death makes for lively reading.

Twenty-one years ago, as readers of the memoir My Year Out will know, McCrum suffered a near-fatal stroke. At just 42, he entered ‘the antechamber to the grave’; and, although he made a good recovery, he has lived, ever since, with an acute apprehension of mortality. ‘At least half my adult life,’ he says, ‘has been spent in the psychological equivalent of A&E.’ Rather than jolly him along, friends and acquaintances feel compelled to share with him their troubles — their illnesses, depressions and bereavements. ‘I am,’ he says, ‘a lightning rod for the unwell.’

But a new phase has begun. As his contemporaries enter their sixties, they are becoming aware that their Biblical span is running out, and, like Prospero, that their ‘every third thought’ is of the grave. And for baby boomers brought up in the 1960s, this can be exquisitely lonely: they are the ‘I-Me-Mine’ generation. They don’t say ‘I am involved with mankind’, but ‘I am involved with myself’. So for them, and for himself, McCrum has embarked on a year’s journey, braiding together passages of literature and encounters with neurologists, cancer patients and hospice workers to try to provide some comfort as they ‘journey down a one-way street towards an inevitable destination’.

Nobody McCrum chooses to talk to believes in life after death — though the psychologist Adam Phillips, whom he visits in his Notting Hill eerie, refers to his ‘ongoing’ relationship with his dead father — I’d have loved him to say more. And in a post-religious age, McCrum believes, it is culture that can provide the best consolation as the darkness closes in. The crowds attending concerts, exhibitions and arts festivals are mostly, he says, over 50: ‘For every Harley-Davidson propped outside the marquee, there will be a dozen wheelchairs within.’

Of all the arts, McCrum has drawn most strength from literature. He cites, with easy acquaintance, writers from Wittgenstein to Proust, from Lewis Carroll to Martin Amis. In his hugely successful working life, he lived and breathed books — first as editor-in-chief of Faber, and then as literary editor of the Observer. So it’s dismaying to find that, in his mid-sixties, he is beset by feelings of regret and failure.

And he’s not alone. Adam Phillips confirms a great fear of oblivion in patients who have a ‘feeling of not having lived. Some people want to mourn the death of a life that never happened’. No comfort for them in the fact that life expectancy increases year on year — more than half a million people worldwide are now aged 100. The third age can be a grimmer prospect than the third thought.

But decline and denouement need not be so bleak. Adam Phillips’s own belief is that

every stage of the life cycle is potentially interesting. And it’s particularly interesting if you don’t think of it elegiacally, if you don’t think, ‘What have I lost?’ but instead, ‘What can I do now?’

For several of the friends McCrum talks to, including the poet Clive James, coming face to face with death has made them more alive than ever.

But there is one form of death — or death-in-life — that petrifies everyone. There are more people in the UK with Alzheimer’s than live in the city of Liverpool; yet nobody has anything approaching a cure. Andrew Lees, who specialises in the disease, tells McCrum it’s ‘a plague’; the novelist Stephen King says he fears it more than death.

I wonder. In January, my father died after suffering dementia for several years. He had never been an easy person, and in the early stages of the disease he became very difficult indeed. But in his final year he underwent a transformation, becoming gentle and full of wonder. It was as if, in stripping him bare, the dementia had exposed a sweetness he had left behind in childhood. A nurse who looked after him told me she sees this often. She was a modest person, probably paid a pitiful wage, lowlier than anyone in this book. But she made me think that workers at the coalface have stories worth hearing.

‘Let us disarm Death of his novelty and strangeness,’ proclaimed Montaigne. McCrum doesn’t quite do that. But he carries us with him on a tour d’horizon that is witty, companionable and compulsively readable. And in the final pages comes a twist to make the heart soar: evidence that however bleak, however short the time left, it is never too late to be surprised by joy.