Robyn Davidson had trekked solo across Australia's outback. But her latest adventure, living with India's nomads, was a far tougher ride. She talks to Rosalind Sharpe
If you ever feel stifled by the sheer comfort and convenience of modern life, and dream of escaping to some far-off desert and wandering with the nomads, don't do it. Robyn Davidson did, and her experiences in Rajasthan and Gujarat, in western India, nearly killed her. What with the biting camels, and the language barrier, and children laughing at her while she had diarrhoea (in public), and the tribespeople she was supposed to be making friends with throwing stones at her, and then offering to let her herd their animals while they rode in her jeep, she spent a lot of the time wishing she had never started.

But she survived, and now, having been tongue-tied for a couple of years by the "unresolved fury" the trip left her with, she has written a book about it. It has evocative cover photographs of camels being led along a sand dune, but it is more about Davidson herself than about the Rabari, the obscure caste of camel-herders she tried to get to know, on and off, between 1990 and 1992. She says Desert Places is about coming to terms with failure. It is also, perhaps less intentionally, a warning about the hazards and humiliations that lie in store when we try to find out what other people's lives are really like.

Robyn Davidson is 46, unmarried, restless, childless. ("When I was young I thought I wouldn't be a good mother. Now I think I would be, but I'm too long in the tooth".) She has lived all over the place. When you meet her she is humorous, frank and friendly, as you would expect from her book, but doesn't seem unstable, or impervious to embarrassment, or crazed with a desire for publicity, as you might also expect. On the contrary, when I went to her flat (one huge, bright room with a tiny bathroom in a former shoe factory in east London I found a scene that could have been the opening shot in a film about a nice woman who, given the choice, prefers to lead a quiet life at home with her cats and pretty knick-knacks. Opera on the stereo, a Scriabin score on the gleaming new grand piano, tea served in china cups and saucers.

Davidson herself didn't look weatherbeaten or even grubby: she was ladylike in a sweet, flowery dress, with her hair in one of those styles that seem to be piled up and falling down at the same time. Could this be the woman who slept with rats, punched slavering dogs, drank and washed in water with turds floating in it, and brazenly enlisted scores people to help her achieve her goal? The woman who was constantly asked, and never able to answer the question, "You have lakhs [thousands] and lakhs of rupees, and you have a jeep. Why do you want to live with poor people? Why do you want to walk?"

Why, indeed, did she do it? There are several understandable reasons. She had been interested in the Rabari since 1978, when she first saw them gathering for a camel fair in Pushkar. They looked exotic, with their clinking silver jewellery and swirling clothes. She noticed them because she is drawn to nomads, whose ability to survive off the land with only such equipment as they can carry she sees as "the paradigm of human intelligence". She persuaded National Geographic to commission an article about them, thus financing the expedition. She had trekked with camels before. And she was beginning to fall in love with a mysterious man called Narendra Singh Bhati, a landowner and former MP who lived (in some style) in Rajasthan.

This blurring of professional and personal motives may partly explain why the trip was so stressful. But the mind-boggling question is why she kept going when it was clear that the enterprise was deteriorating into farce. "I didn't expect it to be so bad," she says, "and then, once I had started, I kept hoping it would get better." She didn't want to let the magazine (or perhaps Narendra) down. Not masochism, she insists, but guilt and stubbornness are the explanations.

Davidson was troubled by feelings of "shame and fraudulence" as she moved between her two lives in India: pretending to be one of the nomads for a while, sharing their anxieties about wool prices and shrinking pastures, drinking camel milk, not washing; then finding a telephone, summoning her jeep, and driving back to an air-conditioned hotel room to clean up and recuperate.

Telephone? Well, these particular nomads don't go in for long journeys across trackless deserts. They may be away for months at a time, but India being India, crisscrossed with roads and railway lines, they are never far from settlements - and thundering highways, nuclear power stations, factories, polluted rivers, petrol pumps and satellite TV.

The point, she says, was "to get as close to these people's lives as possible," which to her sorrow proved to be not very close. "Real travel," she writes, "would be to see the world, for even an instant, with another's eyes." To her great credit, she does seem to have "connected" with a number of people, especially the family with whom she lived and travelled for a few months. They seem fond of her and flattered by her interest, and she still goes to see them. One of the nice things about Davidson is that she always saw the Rabari as individuals and potential friends, whereas a professional anthropologist might have viewed them as objects of interest. But her amateurism was probably her undoing. The cultural and linguistic barriers were too great: "I never felt I approached getting an understanding of where I was."

Davidson may inherit her restlessness from her father, an Australian adventurer who spent the inter-war years killing crocodiles and prospecting for gold and diamonds in South Africa. Back home he became a cattle farmer, and Robyn was born, the younger of two daughters, in 1950, in Queensland. When she was 11 her mother, a severe depressive, killed herself, an event that Davidson, then at boarding school, says she blocked out and has only recently begun to grieve about. She was a good enough pianist to win a scholarship to music college, but didn't take it up. "I was too interested in life."

The next 10 years seem to have been spent searching for the right thing to do. She started a university course in biology, gave up, started another in Japanese and philosophy, gave that up. There were odd jobs, from artists' modelling to playing poker, while she resumed her music studies.

Then, in the late Seventies, she bought some feral Australian camels and took them, alone, on a 1,700-mile trek through the Australian outback. The book she wrote about it, Tracks, made her temporarily famous, and fame brought some exciting friends, including Julie Christie, Doris Lessing and Salman Rushdie, with whom she had a three-year affair.

Since Tracks, Robyn Davidson has made a living as a writer (although she now says she hates travel writing). She has published a collection of essays, Travelling Light, and a novel, Ancestors, about a woman's inner journey into her past.

But when you have done something as sensational as the outback trek, what do you do next? That it must have been tempting to try to do the same thing again is understandable. But Australia, with its empty, hygienic spaces, sprinkled with people who understand English, was unimaginably different from India. Davidson was baffled and frustrated by "Indianness", and found herself becoming critical and judgemental - the sort of person she despised. The longer she stayed, the angrier she got: with the inequities of the caste system, the staring, prodding crowds that surrounded her, the corruption and "guiltless cruelty" she witnessed again and again, above all with the excruciating passivity: "Why didn't people go mad? Why didn't they stab and shoot each other, as they did in America?"

The anger and outrage, because they seem the honest reactions of an unprejudiced woman, make the book memorable, but Davidson is aware of the danger of being thought racist. "This kind of book" - she means one that says negative things about brown people - "can so easily be interpreted in an unpleasant way." The last thing she wanted to do was confirm prejudices.

What about the opposite? Does she still prefer nomads? "I had my bias confirmed," she says. "People who wander are nicer to be with. Movement militates against hoarding possessions and against bigotry, because you are constantly moving across boundaries and having to negotiate with people. I would say they have a bigger sense of the world."

'Desert Places' by Robyn Davidson is published by Viking on 30 May, price pounds 18.