AT THE BEGINNING of Isabel Fonseca's first novel, Attachment, a woman waits for her mammogram in a clinic on St Jacques, a fictional tropical island. There is a framed poster on the wall “of a vagina and a womb - in the family of the butcher's chart, sectioned, coloured, and neatly labelled in teachers' script”.

Jean Hubbard sits in her paper gown thinking how, in England, the examination room would have been decorated with a picture of wild ponies on Exmoor, or Brighton Pavilion, and in the States, “fall foliage on Capitol Hill”.

Jean is an American health columnist, married for 20 years to Mark, an English advertising executive. The Hubbards are on sabbatical in “paradise” while Vic, their almost grown-up daughter, remains behind in the family's London home.

The idea of a sabbatical is attractive, but the reality often more challenging and personally exposing than the connotations of holiday and time off suggest. Fonseca shows Jean stripped of her habitual routines, facing her mid-forties self and body, in the unforgiving bright light of St Jacques.

The mammogram (which proves disconcertingly inconclusive) coincides with the arrival of a smutty letter for Mark, which Jean intercepts. It is addressed to “Thing 1” and signed “Thing 2”. “I'm going to send you a reminder to drool over, you unbelievably filthy old man, if your (sic) not too senile to open the attachment”, the letter promises, providing details of a new hotmail account and password.

Thing 1 and Thing 2 are named after the anarchic forces from Dr Seuss's Cat in the Hat. The prim fish in that book warns: “Those things should not be in this house! Make them go!” but the fish is a spoilsport and the cat's naughty wisdom is more attractive: “It is fun to have fun/ But you have to know how.” Jean, it seems, has not had enough fun in her 45 years. Without mentioning anything to Mark, she goes to the local café and accesses the dirty pictures that “Giovana” has obligingly sent him.

Fonseca writes with steely precision about Jean's overlapping states of loneliness: the isolation of anyone threatened with terminal illness; the solitary rewards of pornography, or sexual arousal without attachment: “Jean wondered what kind of experience PVC bustiers promised - if, just possibly, all this theatrical strut and know-how went beyond sex toward a counterintuitive, post-feminist liberation. Would she, in her own future happiness, dress like this? The word ‘negligée' could mean ‘neglected', Jean thought while examining Giovana in a filmy transparent babydoll of tan-enhancing blue, but it might also mean ‘to give little thought to' - to be cool.”

Back in London for further tests on her breasts, Jean feels grateful to her affluent Harley Street doctor for overdressing: his high-coloured shirts, ties and expensive waistcoats show “an understanding of the physics of the relationship: if someone had to be undressed, the other should be dressed enough for two”.

But Jean is wrong: the physics of the relationship are unchanged from the stark encounter in St Jacques, where she saw her breast slapped on the mammogram machine “like pastry dough”; it's just the etiquette that is different in Harley Street.

Post-biopsy, Jean goes out with one of her husband's colleagues, gets drunk, has a night of wild sex, and the next morning is dismayed to discover that her new-found enthusiasms have been extensively photographed. Her embarrassment is pierced by suddenly remembering her daughter, aged about 6, peering up at the sun over the Odeon cinema in Parkway claiming: “I'm making a memory.”

In contrast to the St Jacques and London sections of Attachment, the New York interlude is brief and rushed. Jean is summoned back to the city of her childhood when her elderly father is taken into hospital. Here she is helped practically and supported emotionally by her old boss, a man she might have married long ago. The old attraction is still there but they don't go to bed, “not because they were married to other people, but because a lifetime was a lot to compress”.

Attachment faces the uncomfortable subject of female ageing with wry, disabused humour. You might come across other reviews or articles that are distracted by extraneous matters such as who Fonseca happens to be married to.

I suggest that you ignore them and read her book on its own feminist (or post-feminist) terms.

Attachment by Isabel Fonseca
Chatto & Windus, £15.99; 320pp
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