It is not every book that is launched with splendid parties at the British Embassy in Paris and the French Embassy in London. Yesterday, an array of guests as glittering as the four pages of acknowledgements that preface the book assembled in Kensington Palace Gardens surrounded by the French Embassy's spectacular tapestries to sip champagne and celebrate the publication of Paris After the Liberation by the husband and wife writing team of Artemis Cooper and Antony Beevor.

It is not every book that is edited by the late Jacqueline Onassis. It is not, indeed, every book that finds itself stingingly reviewed by Jan Morris in Saturday's Independent with the words, 'It is certainly no fault of the authors that I disliked almost every page of this substantial book.' (It turns out not to have been the book Ms Morris disliked, but the characters in it, with the sole exception of General de Gaulle.)

To my mind, Paris After the Liberation is a wonderful book - packed with detail, evocative and full of revelations. But, it must be said, much of the gratifying attention it is getting is due not so much to the book's qualities as to its authors, and particularly Artemis Cooper. For Artemis (that is, Artemis Alice Clare Antonia Opportune) has been an object of interest and patronage all her life.

Her grandmother was Lady Diana Cooper, the most beautiful and beloved society woman of her time; and her father is John Julius Norwich, aesthete, linguist and charmer. Her grandfather, Duff Cooper, was, as it happens, British ambassador in Paris from 1944 to 1947.

'I can see that I was given extraordinary opportunities but, to do myself justice, I did make the most of them. Both my parents and grandparents had great intelligence as well as social glamour.' But she was very intimidated by them.

'I didn't know how I would ever match up to my grandmother. I felt I was bound to disappoint all those people around her who were forever saying, 'Gosh, isn't she marvellous? Isn't she beautiful?' My father was the same. But then I would meet other people's parents and realise that at home we talked about interesting things and other people talked about money and work.'

Artemis and her husband and co-

author live in a handsome house in Fulham, London. The exterior is painted dark green ('It used to be black,' Antony says, 'but the neighbours objected rather') and covered with trailing jasmine. Antony had lived here in splendid bachelordom before they married eight years ago, and at first Artemis wondered whether she could feel at home in what was very definitely his house; but she has managed it, and added her own possessions to his eclectic collection.

The drawing-room in which we talk is decorated in an aubergine-purplish navy. 'Antony mixed it himself,' his wife says. At the far end hangs a large portrait of her great-grandmother, another famously beautiful woman. Violet, Duchess of Rutland, has deep-set, dark blue eyes; Artemis, three generations later, has just the same eyes. The room is filled with impressive pictures and heirlooms - what she calls 'family pieces' - from both sides. Barely an object in it is contemporary, except for a tangle of push- chairs in one corner.

Ms Cooper is wearing a white cotton shirt and denim skirt, her hair tied back, no make-up. She is apprehensive about doing this interview without her husband, insisting that they collaborated equally in writing the book. (He undertook most of the basic historical research; she went and talked to people.) But a married couple is impossible to interview, since each vets the other's every remark, and she submits. He disappears upstairs.

They have a nanny for their daughter, Nella, now aged four, and 18-month-old Adam, and a domestic life of enviable equality. 'I cook and Antony washes up. I never have that nagging resentment, feeling that I do the lion's share. He does all the gardening and the bill-paying and I do most of the children. We work very well together. It's been a very satisfying marriage, and the children feel that happiness.'

Of her own childhood, she says: 'Nanny was the centre of one's life: far more so then than nowadays, though I couldn't do without Nicky. I was a dreamy child, never paid attention at school, not much good at making friends. My father was a diplomat in those days, so I spent my first years in Yugoslavia and Beirut, which gave me a taste for the Middle East . . . its hot sun and exotic smells.

'I learnt French in Beirut at the age of four or five, and grew up bilingual. When we came back I went to the French Lycee for three years and then to the Convent of the Sacred Heart at Woldingham, because my mother's Catholic family put pressure on her. Until then I'd been thoroughly secular, so Roman Catholicism was heady stuff. I was very religious at school and although I'm more sceptical nowadays, I still have that basic ethical structure.

'Then I was sent to Camden School for Girls. It was the time of the Vietnam war, and I thought Armageddon was upon us. It was the most unhappy time of my childhood. In the convent we had been taught that Communism was the force of darkness in the world, and suddenly I found myself in this school where everybody seemed to be a Communist, going on demos for Vietnam. To give the nuns their due, they were only trying to bring us up to be good Catholics and decent people, but that indoctrination did set me back.

'Once I'd adjusted to Camden, I was very happy and it was a much more stimulating atmosphere. But I didn't want to go to university, nor were my A- levels particularly distinguished, so I became a picture restorer for a while. My father was chairman of the Venice in Peril appeal at the time and he got me a job in Venice, in the Abbey of San Gregorio. I learnt Italian and got to know Venice.

'I shared a flat with a girl with the wonderful name of Querina Querin who was also a restorer, working on the Tintorettos in San Rocco. I joined her: and if you would care, next time you're there, to look at the San Sebastian, most of that was me. But restorers as a breed are quite grumpy - probably from breathing all those foul fumes - and it's quite tense, working in microscopic detail. I knew I couldn't go on doing that for eight hours a day, so I came back, without a clue what on earth to do next.

'As luck would have it, staying with some people in the country, I met Lord David Cecil. He was a dream. He told such marvellous stories. He said I should try for Oxford, and when I said, 'I can't, I haven't got O-level Latin', he said, 'Don't worry, I'll introduce you to Rachel Trickett' (who was a don at St Hugh's) and she didn't seem too bothered.'

Ms Cooper is perfectly frank about the power and extent of her family contacts, which secured her a job restoring flood- damaged paintings in Venice that most people, some much better qualified, would have given their eye teeth for; and got her into Oxford to read English without the then obligatory Latin. Later, when she wondered about theatre design, her grandmother immediately offered to ring up Lord Olivier. It isn't fair, and she doesn't try to pretend it is. But she did work hard at university.

After that she spent a year teaching English in Alexandria with VSO.

'I only got out from under the great weight of the family when I went to America. Nobody there had a clue who Diana Cooper was. I did the usual things like being a waitress and thought, gosh, I can be myself; I am my own person]'

She also got married while in America, although she fails to mention this during our interview, to a man she met in Boston. The marriage was brief, and childless. Later on she says suddenly, 'For me, most love affairs have started off as friendships. The great emotional leaps have been the disasters: when you're caught in a sort of fantasy. I don't like talking about them because they seem like part of another world.

'In 1980 I came back to London and worked for the National Trust for a while, but I was at a loose end when Philip Ziegler, who had written a biography of my grandmother, asked me to edit her letters: and that (A Durable Fire) was my first book. I suddenly thought, at last, this seems to be it]'

That book was published in 1983, not long before the death of Lady Diana Cooper at the age of 92. Two years later, Artemis met Antony Beevor. By this time they were both in their thirties. 'Funnily enough it seemed to be a relationship very much based on friendship rather than white-hot passion - though it was, and still is, very passionate. The core of it is a kind of complicity; the being together that I've always looked for.'

Their life together might have seemed almost too perfect, were it not for their first child's near-fatal illness in September 1990. That was every parent's nightmare. Within hours, a healthy eight-month-old baby turned into a desperately sick one.

Nella was in hospital for several weeks, suspended between life and death, before a resourceful doctor and a new 'miracle' drug called EGF, pulled her back to life. 'Our consultant had worked in a laboratory where this stuff was developed. ICI donated it, and within days we could see the improvement.

'The thing with Nella made us a lot stronger. Antony said, 'Even if we lose her we'll still be together', and that was the most wonderful feeling: that he'd always be there.' Her voice breaks. It was nearly four years ago, yet she still cannot talk about it without being overwhelmed by emotion.

Ms Cooper kept a diary during those weeks and afterwards, in 1993, published Watching in the Dark, a moving account of Nella's illness. 'The effects of that were fairly rough. I was very depressed for a long time afterwards, and felt as though my batteries were totally drained. I had no balance, no sense of proportion, and my temper was very volatile. It took a year to come full circle. I had poured out everything, and it took time to replenish. And then I suddenly found I was pregnant with Adam.'

What were the after-effects upon Nella?

'She may have fears and terrors but if so, they're in such a deep dark place that it's not obvious. Children of that age have amazing recuperative powers. Yet we took her with us to the paediatric ward recently, because Adam had to be checked out, and at about one o'clock that morning she started screaming in agony. She was clutching her stomach, fast asleep, and I couldn't wake her up. So maybe it's all there in her unconscious, and being at the hospital brought it back.'

Nella, now a bright-eyed little girl, returns from school with her nanny at this point. Antony emerges from upstairs with the newly awakened Adam in his arms. They all go through to the kitchen. 'More coffee?' asks Ms Cooper politely. I decline, admire their garden with its magnificent lilies, and leave them to their children, and each other.

'Paris After the Liberation' by Antony Beevor and Artemis Cooper, is published by Hamish Hamilton at pounds 20.

(Photograph omitted)