'A lot of the stories were written out of a response to travel accounts to Thailand, where Thai people were in the background, being used as props for a middle-aged white character, and the Thai people tended to speak in clipped sentences and didn't seem like the Thai people I knew,' Lapcharoensap says. 'The characters and stories were created out of a desire to see a much broader Thai humanity.'

But he has no illusions. 'I don't speak for the Thai people and for Thailand,' he says. 'I'm simply attempting to create characters I love and to render people as realistically as possible.'

Lapcharoensap netted a six-figure contract for Sightseeing and his novel-in-progress. He's the recipient of a David T.K. Wong fellowship, through which he's spending a year at the University of East Anglia in Norfolk, England, working on the novel. So the citizen of two countries has adopted a third - at least, until July, when the fellowship ends.

He's taken time off from writing to promote Sightseeing, which has been published in 11 countries (although not China). The print run in the US is 20,000 - large for a first work of fiction - and his book tour has been extended from 15 to 18 cities.

Ithaca has special meaning for Lapcharoensap. It's the city where he attended college, Cornell University, and first became interested in writing. Like many expatriate writers, Lapcharoensap's interest in literature initially grew out of loneliness. 'I feel like I've come full circle,' he says. 'This is where I got serious about reading English-language literature.'

The warm reception Lapcharoensap receives at his readings, mostly in independent bookstores, contrasts with his early experience of the US. Born in Chicago, where his parents had immigrated to escape the Thai military's 1976 crackdown on leftist students, he soon felt like a second-class citizen - a feeling that has cropped up again in his post-September 11 travels. 'I get frisked by security every time I'm in an airport,' he says. 'I fit a certain profile: twentysomething, dark-skinned young man.'

In Chicago, his father was a cook, his mother a babysitter, and the family was poor. They rented a one-bedroom apartment on the rundown south side of the city, and he and his younger sister - now 22 and a neuroscientist in New York - wore hand-me-downs. Lapcharoensap still sounds angry recounting how his family was denied service at an ice cream store in a fashionable neighbourhood. Highlighting his sense of alienation, he was bussed from the south side to an elementary school in one of the city's most upscale districts.

After the military crackdown ended, his family moved back to Bangkok. There, his parents were middle-class professionals who owned a house and a car. 'How you can be one thing on one side of the ocean and another on the other side gave me an awareness of social class - how completely contingent it is,' he says.

This awareness figures amply in his fiction, along with an ambivalence towards Americans and the US. Most of the stories are narrated by precocious and impressionable children or youths, absorbing harsh lessons about status just as he once did.

In the story Farangs (Thai slang for westerners), the American tourists are stupid and boorish to the point of being destructive. The only thing they have over to the locals is money, which buys them freedom to travel and a sense of superiority.

Money also causes trouble in Draft Day. A well-to-do, connected young man is ashamed to tell his poor friend that his family has paid off a military officer to stop him from being drafted. The poor friend is drafted, and the friendship dissolves when the ruse becomes apparent.

In Priscilla the Cambodian, a girl manages the Herculean feat of hanging on to her dignity despite her destitute circumstances. Priscilla and her mother are refugees, which makes them the lowest form of life in every community where they try to settle. The cruelty of the Thais who burn down the refugees' shantytown, and the corruption that tears apart the two friends, shows Lapcharoensap's ambivalence towards Thailand, as well, and his ability to capture both its beauty and depravity. 'When I write about Thailand, I'm writing as an outsider and an insider,' he says.

Illustrating this conflict, of all his characters, he identifies the most with 'an old American man in Don't Let Me Die in This Place, ' Lapcharoensap says. 'He suffers a stroke and goes to Thailand to live with his son and Thai wife. There's a sense of impotence and rage at being caught between different categories - neither tourist nor native, neither home nor abroad.'

The book's title story - set on one of the Andaman Islands, an area hit hard by the tsunami - explores the notion of being a tourist in one's own country. A young man and his mother visit the island before the mother's progressive blindness makes this impossible.

'That story is about a son's devotion to his mother, and they're going sightseeing,' Lapcharoensap says.

'They're lower-middle-class Thai folks trying to behave like tourists. It's about what it means to look at a place, to look at one's loved ones, what it means to witness the frailty of your elders, to witness them becoming sick and going fragile, and also to look at a place like the south of Thailand. I'd always been curious when I saw tourists come to Thailand. I'd wonder, what the hell did they come so far to witness? My own life felt so boring, and I just wanted to get out of Thailand. Yet here were all these people coming from so far.'

In light of the tsunami, the last sentence of the story takes on eerie significance: 'I'm walking onto the sandbar, warm waves licking up across my bare feet, out to watch the sun rise with Ma, and then to bring her back before the tide heaves, before the ocean rises, before this sand becomes the seafloor again.'

'Suddenly, that story had a context it didn't have before,' Lapcharoensap says. 'It was just an accident that the line came out as it did. That story is based on real areas in Thailand that had a lot of damage.'

Although the tsunami turned the world's eyes to Southeast Asia - and boosted interest in his book - the circumstances make the attention bitter, Lapcharoensap says. 'It makes me feel incredibly dirty. The tsunami spooked me incredibly. I couldn't write for weeks afterwards. You can't read this book and not think about what befell that region. I think a lot of people had trouble understanding the region before the tsunami. Afterwards, people have a much more concrete understanding of the geography of the region.'

The tsunami destroyed his aunt's beachfront hotel, the inspiration for the one in Farangs. He plans to visit Thailand within a month to see the devastation first-hand. In contrast, when he was a struggling student, three years once passed between trips to Thailand. Now, he returns at least once a year.

This is Lapcharoensap's first taste of financial freedom. After the 1997 economic crash in Asia, his parents stopped sending him money. While at Cornell, he worked three or four odd jobs simultaneously to support himself, leaving little time for writing.

It was at the University of Michigan, where he earned a master's degree in writing, that he began to focus on the craft in earnest. But at first, literary recognition was as elusive as financial stability. 'I went through a three-year period where I was sending stories to journals and getting the customary rejections,' he says. 'For a long time, it felt like nobody was interested in Thailand or my work.'

Eventually, four of the stories in Sightseeing were accepted by literary journals. He had completed all the stories in the book by February last year and landed a New York agent, Amy Williams at the Collins McCormick Literary Agency. They sent the book out to publishers in April and, just days later, were juggling offers.

'I sent it out on a Thursday and heard back on Monday,' he says. 'I was shocked. I thought my literary tree would fall in the forest and that would be it. It's one of those things I had built up so much in my mind - I didn't expect people would want the book. I've always had an enormous amount of self-doubt about my writing. It's never as good as it can be. When I'm doing a reading, I find myself making corrections to the book. I don't read it the way it's published.'

Although Lapcharoensap has become accustomed to a more comfortable lifestyle, he still has trouble accepting the critical acclaim his book has generated. 'After a while I realised that people who were coming to my readings actually liked my book,' he says. 'I'm kind of neurotic about those things. I thought I'd be called out by the fraud police and they'd show up at my readings. But I realised people are here out of generosity. That's been a good discovery - that my fears and paranoia are unwarranted.'

A still-unrealised dream is for the book to be published in Thailand. 'I'm hoping desperately to be able to sell the rights to Thailand,' he says. 'It would make me incredibly happy. My mum could understand what I do. I'd like to know what a Thai readership thinks of these stories. I think it would be different from the American response. The Thai government has been particularly sensitive when it comes to the representation of Thais - they feel it's been overdetermined by sex and drugs, rightly so - so I'm curious to see what its response would be.'

His novel-in-progress, tentatively titled The End of Siam, will tell the story of Thailand's modernisation in the late 1930s. 'My immediate goals are to get home - wherever home is - and start writing again.'

The new British edition of Sightseeing (Atlantic) sells for $150.