When Katherine Wilson arrived in Naples for a three-month internship she didn’t realise the chaotic city would provide her with a husband, a family and a remarkable guide to the arcane local culture in the shape of a no-nonsense Neapolitan mother-in-law.

 Migration memoirs have become a lucrative and crowded publishing niche, with books often followed by cinema spin-offs.

 British author Peter Mayle blazed the trail with his 1989 “A Year in Provence”. He was followed by Chris Stewart, whose “Driving Over Lemons” – about life on a farm in Andalucia – spawned so many imitations that his publisher named its slush pile of unpublishable manuscripts “the fruit bowl”, as they all had a fruit in the title.

 Italy has proved a popular destination for these rites of passage memoirs, notably with Frances Mayes’ “Under the Tuscan Sun” and the more recent “eat” section of Elizabeth Gilbert’s 2006 “Eat, Pray, Love”.

 Eating is the fundamental theme in Katherine Wilson’s “Only in Naples: Lessons in Food and Famiglia from my Italian Mother-in-Law.”

 Mastering Neapolitan food culture -- an expression of nurture, comfort and love -- proves important in helping the young American from a wealthy east coast family to overcome her binge eating disorder and develop a less conflicted relationship with her body.

 A Neapolitan student friend puts her finger on the problem when she tells Katherine that she comes from a country of messy, disorganised eaters. In Naples you eat unhurriedly, in company and at meal times, “without distraction and preferably with a glass of wine.”

 Converting to that Mediterranean approach, and to freshly cooked Neapolitan dishes, puts an end to the bingeing. “There were no additives to make me crave more. For the first time in my life I could, along with the rest of the city, get up from the table and not think of my stomach until the next meal,” Wilson writes.

 Embedding with a middle class Neapolitan family gives an extra dimension and piquancy to Wilson’s tale of cultural dislocation. Naples is already a challenging destination, somewhere dirty and dangerous that her family would pass through quickly on its way to Pompeii.

 “My grandfather, whose parents were from Calabria, said that Neapolitans could steal your socks without taking your shoes off,” she writes.

 Wilson provides a humorous account of the cultural gap between her eccentric Washington family and the deeply Neapolitan Avallones, which emerges in the home, at the shops and, particularly, in the kitchen.

 “My mother did not have any sort of relationship with any human being at the suburban Safeway where she shopped when I was growing up,” she observes. In contrast, the man running a salumeria in Marechiaro, visited for the first time, takes trouble to advise on the best combinations for family sandwiches and marks each package with individual names.

 Naples’ contradictions are on show when it comes to healthcare. After fainting on a bus, Wilson finds the vehicle has changed course to take her to hospital and she has been entrusted to the care of a kind middle-aged lady who happened to be travelling with her. Having arrived at the hospital, though, one is not necessarily out of the woods.

 Naples hospitals are places where doctors smoke in the halls, no one repairs a broken generator, and you risk dying of a perfunctory diagnosis, while nurses are too busy talking on their cellphones to attend to your needs. “Insomma, a hospital where unless you have some loving, smart, pushy relatives to take up your cause, you might be better off never setting foot.”

 Wilson explores the different moralities of Protestant America and superstitious, Catholic Naples.

 “In Naples, people do not lie. They re-create, artistically and playfully, their own truth. It is normal to tell untruths, creative reconstructions of reality. These untruths are told with calm and finesse. They are told not only to dupe or deceive but also to protect, out of love for the person being misled,” she says.

 Pinocchio, the northern fable that teaches children not to lie, is eclipsed by Pulcinella, the southern clown who teaches them not to get caught.

 Nonna Raffaella, the formidable mother-in-law, illustrates the kindly lie when Wilson’s young son is frustrated at his inability to catch fish. Wilson sees it as an opportunity to teach her son about the virtue of patience. “It’s about the process, not just the result,” she maintains.

 Nonna Raffaella has a different idea. She disappears to a nearby restaurant and reappears with three dead fish and a pasta strainer, proceeding to persuade her grandson that he had succeeded in catching “a rare, delicious species of headless haddock.” It’s a classic deception “out of love”, and totally at odds with the character-building moral lesson the American mother was intending to impart.

 Wilson’s journey to personal integration in Italy is a far cry from that of the third world migrants hoping for employment as domestic servants among Naples’ well-off local families. Her account shows how the meeting of contrasting cultures can be entertaining and mutually enriching.

 “Only in Naples” lifts the veil on a world that few foreigners succeed in penetrating, but it is also a handbook of wider relevance today, as millions of desperate migrants take a similar route to the one that Wilson explored two decades ago.

 When Wilson reluctantly agrees to take on a nanny from the Philippines, she is convinced the woman would always come a poor second best to Mommy.

 “One of Anthony’s first English expressions was ‘When de Jackie come?’” she writes. Another was “Mamma leave now, okay?” Surprising processes of integration are at work everywhere, and not only in Naples.

 Only in Naples: Lessons in Food and Famiglia from my Italian Mother-in-Law

 by Katherine Wilson

 Random House, pp 283

 £13.48 Amazon

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