Review: Instructions for a Heatwave, By Maggie O'Farrell

This humorous, humane and perceptive domestic saga broils with the resentments left behind by an absent husband and father

Maggie O'Farrell's sixth novel consolidates her reputation as a a writer who depicts relationships with piercing acuity in haunting, intense prose. Her Costa-winning fifth novel, The Hand That First Held Mine, examined the challenges and passions of motherhood; her fourth, The Vanishing Act of Esme Lennox, was set in the 1930s, when a woman could be decreed mad and incarcerated for unconventionality. Her third, The Distance Between Us, a winner of the Somerset Maugham prize, delved into family and sensual love; her second, My Lover's Lover, was about the insecurities that accompany new romance, while her debut, After You'd Gone, won a Betty Trask prize for its harrowing exploration of trauma and secrets.

Instructions for a Heatwave is set during the simmering heatwave of 1976, in a London family seething with tension. Gretta, an imposing Catholic Irish matriarch, is stunned when her husband Robert disappears one morning. Her adult children, Michael, Monica, and Aoife, the latter two estranged, are summoned to help solve the mystery. Each child is burdened with their own problems.

O'Farrell is a deliciously insightful writer, observing the dynamics of relationships and astutely filleting them to the bone. Her sharp but humane eye dissects every form of human interaction. She cleverly leaks signs of familial dissatisfaction: Gretta is not laid open to us through information imparted by an omniscient narrator or by her family's conversations – that would be too easy. Instead, there is telling detail: her compulsive eating; her imposition of Irish Catholic values on her unwilling children; her passive-aggression ("[he] had as good as promised to bring the children over ..."); her self-centred melodrama (the cry of "How could you do this to me?" at someone else's crisis, and the martyr's ululation "You might as well kill me now").

O'Farrell's portrayal of Monica's desperate attempts to win round her new husband's daughters is as sharp as Joanna Trollope's in Other People's Children, and captures the hostility that step-daughters can show for a new wife. Monica's new mother-in-law's preference for her son's previous partner is also subtly but indelibly clarified. Michael's personal woes illustrate that infidelity is not solely the terrain of ogres, as depicted by some monochrome authors, and that fathers can feel discarded when children arrive; excluded from the biological closeness between sons and their mother.

O'Farrell is exemplary on details, such as the dangerous unpredictability of a marital argument: Michael and his wife Claire have "one of those terrifying rows where suddenly an end you never thought would come rears up in front of you, like a cliff edge you weren't aware of. A row in which you can hear the roaring of the sea below, the boom of waves against the rocks."

And O'Farrell infuses humour into stressful situations: Aoife's irreverence in the face of her mother's religious fastidiousness is a joy ("He's gone and knocked up a Prod"), and O'Farrell is excellent on Michael's first meeting with Claire's upper-middle class parents: their studied, convoluted politesse ("would he mind awfully passing the butter?"); the relentless questions posed from behind a facade of avuncularity but intended to judge his acceptability as a suitor; the faint disapproval at otherness; and the interrogated Michael's deranged urge to shock.

O'Farrell is also marvellous at depicting the delights and hazards of small children: their honesty, the way they interact with and learn from adults, and the travails of child-minding. The final scenes of the family's trip to Ireland is as perceptive on the jaggedness of family forced together as Colm Tóibín's The Blackwater Lightship.

The only disappointment is the Hollywood ending: Robert's exoneration seems a cop-out. It would have been a more intriguing story if he had walked out for less munificent reasons, like most people who walk away from long-term relationships. Paul Morley's memoir Nothing was mesmerising in its desperation to make sense of his depressive father's final, unannounced escape from his family. The reasons why people fall out of love and tolerance; the way in which a partner's previously endearing traits curdle into irritation: these are avenues that I craved for O'Farrell to explore. Not a neat justification of Robert's disappearance, through a vaguely implausible plot. Aoife's side-story, in which the reader worries that she will drive away her boyfriend by not confessing a secret, is similarly tidy: we wait anxiously for her to reveal all to him and she does.

There are some possible anachronisms: in the 1950s, buses didn't have doors that opened automatically, and did purposefully distressed "shabby chic" furniture exist in 1976? Still, tiny quibbles can't detract from the sensuous pleasure of O'Farrell's insights and heady, evocative prose.