Julian Barnes tells us that this is his final book, so that’s one departure accounted for – the last instalment of a writing career spanning 45 years, encompassing novels and short stories, memoirs and essays, biography, travel writing, translation and even a little pseudonymous detective fiction. Many of these works turn up here, whether obliquely or overtly, referred to through subject matter, style, tone or connotation; in the contemporary cultural argot, which Barnes is fond of examining, these writerly winks might be known as Easter eggs.

The other form of leave taking is the “departure without subsequent arrival”: death. It is, as Larkin had it, “no different whined at than withstood”, and the truth is that most of us are both whiners and withstanders, querulous until there’s nothing left to complain at, stoic until pushed too far. Barnes is perhaps the great interpreter of mundane grandiosity, or grandiose mundanity – understanding that even as we attempt to inhabit the heroic mode, or to reach an intellectual accommodation with both mortality and morality, we will slip on a banana skin (or in Barnes’s case, he tells us here, a wooden staircase approached with bath-damp feet in a rush to answer the doorbell).

His novels are littered with metaphorical slippery stairs; they arrive in the form of love that goes wrong for unforeseen reasons, misapprehensions of memory, gaps in the personal historical record and the sudden intervention of events. But so are most novels. What makes them his is their tone and his extreme control of its variations: the voice is rational but also romantic and rueful, aware that self-assertion can shade into bullish solipsism, that the pursuit of freedom can lead quickly to delusion, of the self or others.

Departure(s) is a novel, but not only a novel; its fictional characters may in fact be real people, according to whether or not we believe Barnes, and there is a significant portion of autobiography, which he dares us to disbelieve (“google that if you wish”). One of these made-up real people would not approve: “This hybrid stuff you do – I think it’s a mistake. You should do one thing or the other,” Jean tells him. Luckily/sadly, she’s dead, and he can tell us the story that he promised her he never would: of how he introduced her to Stephen when they were all at Oxford, witnessed the flourishing and dissolution of their youthful love affair, and then reintroduced them in late middle age only to watch the whole cycle repeat.

To what extent is he to blame for the failure of their second go-round, which seems to be down to a mismatch in romantic (if not erotic) intensity? He had warned Stephen against going back, after all; but has his desire to be integral to a well-orchestrated story caused him to overreach, obscuring the reality, in which he is simply “a seedy marriage-broker”?

The reader is not entirely clear, not least because the ground keeps shifting. We might wonder what Barnes means when he mentions “the mud in his own past” being stirred up, and casually lets us know – deliberately, of course – that he and Jean once found themselves in bed together, rather unsuccessfully. We’re in the delayed slipstream of the character-triangle novels Talking It Over and Love, Etc, and the more recent expositions of the repressed but returning past, The Sense of an Ending and The Only Story.

For all the ostensible practical realism that Barnes imposes on the story, there is evident artifice at work; the characters appear somehow adrift from a recognisable social setting, and the narrator adopts a diffidence (“Do you know what I mean?”) and self-deprecation that ring false even as he appears to doubt himself and his motives.

Whether he’s writing fiction or nonfiction, Barnes is excellent, and always has been, at this kind of Pooterish persona. In the “straight” life-writing of Departure(s), he manages to impose a bathetic humour on his diagnosis with incurable but manageable blood cancer, which happened at the beginning of lockdown. Juxtaposing his memories of the initial event, which had the immediate bonus of getting him out of an Abba-themed wedding reception but few other upsides, he notes that he recalled taking a crossword puzzle and some chocolate along to A&E, but forgot about the piece on the writer JK Huysmans he was working on. “I can quite see why my subsequent anecdotal account suppressed this detail,” he remarks drily, but we’re left to wonder whether it’s because Huysmans would have been too depressing on top of a cancer diagnosis or because the idea of sitting in a hospital waiting room poring over a French symbolist is faintly ridiculous.

But being able to laugh at Barnes – from his fantasy of grabbing squeezed doctors’ attention by wearing a badge saying “BUT I WON THE BOOKER PRIZE” to his endearingly schoolboyish habit of gluing loose pages of his journal into an A4 notebook, year after year – lets other emotions surface. One of Barnes’s cleverest and most humane talents has been to allow us to feel things, ordinary things both trifling and important, about our own lives. The line that brought me closest to appalled tears in this book is a description of an elderly jack russell: “His feet hurt.” I have already recommended Departure(s) to a friend whose childhood memory of Fortnum & Mason is that her father took her there to look at the pork pies: a Barnesian moment, if ever there was one.

Why is he laying down his pen now? Not because his life is in immediate danger; as he tells us, he is as likely to be got by something else as by his “manageable” condition. Maybe a little because, like the novelist Brian Moore, he doesn’t want to die in the middle of writing a book. But the best indication might be his description of the onerousness of creating characters and their endless backgrounds: “Actually, just writing this makes me feel a bit weary.” At the very end of the book, he tells us that he will miss us, his readers. There’s no way to reciprocate without sounding mawkish, but there it is.