An unreliable narrator keeps her husband and readers guessing; the welcome return of burned-out cop Jake Jackson; a multilayered family thriller; and a disturbing boarding school secret

We don’t learn the name of the protagonist of Scarlett Thomas ’s gloriously dark and tangled thriller, The Sleepwalkers (Scribner), for some time, but it’s immediately clear that we are in the hands of that most joyous device, an unreliable narrator, and that she’s out to justify something bad that’s happened. She’s writing a letter to her husband, Richard, to explain why she has left him behind on the Greek island where they’ve come for their honeymoon. Their love, she says, is “forever cursed”; there is another woman involved, Isabella (“I find it so hard to write her name”). We learn of some former guests at the hotel where they’re staying, a couple known as “the sleepwalkers”, who walked into the sea and drowned. Our narrator is prone to the dramatic – looking at a painting of some tulips, she says “the red flowers looked like large wine glasses full of blood, or – and I have no idea why I thought this – stuffed with meat”.

She’s hard to trust: “From now on, everything I say I will imagine you disagreeing with, saying ‘It wasn’t like that’ or ‘You’re not being fair.’” Thomas, author of the acclaimed The End of Mr Y , tells her story through fragments of letters, torn notebook pages and audio transcripts; it’s a lot of fun trying to work out the truth of what’s happened, and I’m not sure I ever really got there, but that didn’t remotely affect my enjoyment of this clever thriller. As one character later says, critiquing one version of the story (because there are many), it’s “too experimental and too dark. They said they still didn’t know who the sleepwalkers really were and who, if anyone, had killed them.” This isn’t too experimental, it’s just dark enough, and I highly recommend it.

The One Day author’s new will-they-won’t-they tale, about two divorcees who find themselves walking the Lakes and Pennines, is a great comic novel – and superb on the landscape

The proximity of the publication of David Nicholls’s sixth novel, You Are Here , to the screening of the superb Netflix remake of One Day gives the new book an added sense of poignancy. If One Day (2009) saw Nicholls as a writer in his mid-40s looking back nostalgically on the loves and losses of twentysomethings, here we find him approaching 60 and turning his attention to a couple either side of 40. If One Day was angst and high drama, the setup here is softer and, initially at least, more obviously comic. But the shadow of the earlier novel, of Dexter and Emma’s will-they-won’t-they romance, hangs over this book.

Michael Bradshaw, a geography teacher reeling from a series of personal setbacks, most painfully his separation from soon-to-be ex-wife Natasha, decides to walk Alfred Wainwright’s famous coast to coast path through the Lakes and the Pennines. His happily married colleague Cleo, despairing at his inability to move on, turns what was going to be a solitary excursion into a party. She invites a motley gang along for the first leg of the walk: Conrad, an “absurdly attractive” pharmacist; Cleo’s taciturn teenage son, Anthony; and Marnie Walsh, a copy editor, “aged 38, of Herne Hill, London”. There was supposed to be another friend, Tessa, whom Cleo had invited as a potential match for Michael, but she drops out at the last minute.

The US author’s novel about a cancelled lecturer in a parallel dystopia that prizes ignorance is missing her usual verve

L ionel Shriver ’s new novel, a hymn to inclusivity and kindness – just kidding – takes place in a parallel recent past as western civilisation withers under the grip of the Mental Parity movement (“the last great civil rights fight”), which insists there’s no such thing as stupidity, preferring to speak of “alternative processing”. Effects run from the retrospective cancellation of Frasier (because the Crane brothers are “brain-vain”) to tens of millions of Covid vaccine deaths (because newfangled employment practices stopped Pfizer hiring qualified staff, resulting in the inadvertent creation of a toxic serum).

World-building as trolling, basically. The saga unfolds in Pennsylvania from the point of view of a contrarian lecturer, Pearson, cancelled amid the war on wisdom after she bravely makes Dostoevsky’s The Idiot required reading – the very title being outlawed, natch – before being caught on camera ranting about “retards”; footage that sweeps through the press, who are more concerned with “cognitive bigotry” than with Moscow and Beijing rampaging through their neighbours “because the western world was wholly caught up in this Mental Parity fiasco”.

A pregnancy leads to the unearthing of a mother and daughter’s secrets and struggles in this skilful debut novel

When Nell, a chef, agrees to try for a baby with her partner, Adrienne, a stylist for celebrity food bloggers, she anticipates failed IVF cycles and a financial and emotional toll that will soon nix the plan. Instead, Adrienne conceives after two rounds, and Nell, terrified of looming parenthood, is pitched into a reluctant reckoning with the ghosts of her teenage years in turn-of-the-millennium Ireland. A cult-like Catholic youth movement, denial of her own sexuality, teen pregnancy – all play their part, and yet even this is not the full story.

Having already caught the attention of prize juries with her short fiction, Niamh Mulvey delivers a questing first novel of significant prowess. Its title refers to the fraught changes to Ireland’s abortion legislation and its impact on women’s lives, her exploration of which is deepened by a second narrative strand: the coming-of-age of Nell’s mother, Dolores, on the fringes of the country’s nascent feminist movement in 1980s Dublin.

The Amendments by Niamh Mulvey is published by Picador (£16.99). To support the Guardian and Observer order your copy at guardianbookshop.com . Delivery charges may apply

The British playwright’s first novel is sweary and saucy but also tender and soulful once it reveals its true heart

Anoushka Warden’s debut novel bowls in from line one like a mixture of Adrian Mole, Victoria Wood, Kathy Lette and a vintage Just Seventeen article that encourages you to look at your undercarriage in a hand mirror: “By my mid-20s I thought I had my fanny and its workings all figured out… I just had this deep trust in it. That it was doing what it was supposed to be doing. Which, primarily, was finding orgasms from all the ways possible to it, ie fingerings, lickings and dry humping.” For the next 40 pages, it proceeds as an “autovagiography”, with the men this “fanny” encounters being ranked on an itemised “Top Humps” scoreboard: “Spanish Alan… always carried lube in a mini bumbag (for his bike).”

Warden is a writer for stage and screen – keeping up the sweary, self-deprecating theme, her debut play was the acclaimed My Mum’s a Twat – and she is skilled at maintaining her narrator’s breezy humour and heartbreakingly transparent facade of streetwise carelessness. But it’s exhausting for the reader, who may wonder why this adult tale is being told with kids’ fiction cadences: her boyfriend’s job “was the sort where he had to sound clever to do it and most of the people who worked in his office had all been to the same university, had very posh accents, were in cricket teams together and shortened their surnames to create nicknames like Diko (Dickens), Wilko (Wilkins), Hamo (Hammings) – which they always said like a football chant”.

I’m F *cking Amazing by Anoushka Warden is published by Trapeze (£20). To support the Guardian and Observer order your copy at guardianbookshop.com . Delivery charges may apply

A fascinating biography of a true British army maverick, an ambitious Cumbrian western and a nuanced novel about a classic modern dilemma

Robert Hutton
Weidenfeld & Nicolson, £25, pp354

To order The Illusionist: The True Story of the Man Who Fooled Hitler , The Borrowed Hills or Second Self go to guardianbookshop.com . Delivery charges may apply

The Booker shortlisted novelist on writing his first significant non-working-class character, the literary critics who inspired him and why he’s not on Facebook

The destructive desires of an inoffensive family man drive this subversive satire of existentialism

For Jean-Paul Sartre’s protagonist in Nausea, it was a stone on the beach that prompted overwhelming abhorrence at the nature of existence. For Rupert Thomson’s Phillip Notman, it is the beep of an electronic reader as it registers a travelcard. How to Make a Bomb (published as Dartmouth Park in the US), Thomson’s 14th novel, opens with Notman leaving an academic conference in Bergen, Norway. He is returning to London, where he lives with his wife Anya. Their son, Seth, has recently recovered from a suicide attempt and is now at university. On the Bergen tram, Notman feels that a “hand had wrapped itself around his brain, and it was squeezing”. Everything around him is suddenly “unbearable” because it is “artificial”.

At the conference, Notman met a Spanish sociology professor, Inés Vaquero de Ayala, younger than him and not a mother, who wears a red organza blouse at breakfast and whose lips make him wonder “what it would be like to kiss that mouth”. “Nothing had happened,” he reassures himself, but something has changed. He stays up late, sitting in the freezing garden of his comfortable north London home. He feels that the remedy for what he calls his “nausea” is to distance himself from the people he loves most. He buys a plane ticket to Spain, explaining to Anya: “I need to work something out.”

American postmodernist novelist whose experimental approach challenged literary conventions

The American novelist John Barth, who has died aged 93, was a noted evangelist for experimental fiction, beguiling his readers with complex stories within stories.

He claimed as his patron saint Scheherazade in the Arabian Nights, the vizier’s daughter whose tales, spun out for 1,001 nights, entranced King Shahryar: “The whole frame of these thousand nights and a night,” Barth said, “speaks to my heart, directly and intimately – and in many ways at once personal and technical.”