'We went out to buy a new suit for graduation,' Ammaniti, 36, says of that day in 1994, the first ever on which he wore a tie. 'I said, 'Daddy, I have to say something to you.''

There was no thesis, he admitted. Instead, there was a story about a fish-breeder. Massimo Ammaniti, a professor of psychopathology, was furious. 'You've lied to me for three years,' he cried.

Contemplating the door, the distraught son reminded his father of the hundreds of fish tanks that crowded the second floor of the home, their contents awaiting eventual distribution among the pet shops of Rome. 'We are 2,000,' he said, referring to his fishy entourage. 'We cannot all leave.'

But his father was serious and the pair didn't speak for six months, until Ammaniti spotted his dad sitting in the front row at a literary event.

'There had been three or four critics who gave the book good reviews,' he says, adding that friends of his father had also read the novel and put in a good word for him with the old man.

Two more novels followed, including the recently published I'm Not Scared (Canongate, $186), which has been translated into 20 languages (including a Chinese edition published in Taiwan) and adapted for the big screen. The Italian-language film will be dubbed or subtitled for international markets and distributed by Miramax.

Set over just a few days during the hottest summer of the 20th century, the novel explores loss of innocence through the eyes of nine-year-old Michele Amitrano. The boy spends his days cycling through the golden wheatfields with a handful of children from his tiny village, while their parents rest inside, avoiding the heat. This peaceful existence is shattered one afternoon, when Michele makes a terrible discovery while exploring a deserted farmhouse. He must deal with the consequences as best he can, guided by a naive but heroic sense of right and wrong.

While the Rome-based Ammaniti denies that Michele's character is autobiographical, the narrative is so reminiscent of childhood that it is difficult to believe him. 'It's normal when you speak about a little boy, you remember when you were a child, all the dreams, the scares and the monsters,' he says. 'These may be mine, but all the other things: the place, the position, the economic situation, are not.'

Ammaniti's sparse, simple prose makes his work a pleasure to read, but it was this style that held him back initially.

'I was always a very big reader,' he says. 'But I'd always thought writers were like superman, with brains that are so big, so incredibly intelligent, that it was impossible for me to be a writer.

'I was very afraid to try writing because if people could understand my brain they'd find that there are only a few things in there, and that they're not very interesting.'

But after switching from Dostoyevsky and Flaubert to American minimalists such as Bret Easton Ellis, Ammaniti developed confidence in his own easy style.

'It's not important to be a genius. You can also write if you're very stupid,' he says.

The far-from-stupid author has since produced a short story collection, won the respected Viaggio-Repaci prize, and been described by Italian newspaper Il Giornale as 'the best novelist of his generation'. Ammaniti, who attended the recent Sydney Writers' Festival, plays down these achievements. 'I'm the best of my building, probably also my block, but that's about it,' he says.

'I don't care about prizes. He writes, he says, 'partly to entertain, partly to say something interesting - it's important that it's a beautiful story'.

The writer made amends with his father in 1995, agreeing to help edit the older man's latest psychiatry text, on adolescent problems, In The Name Of The Son. Ammaniti felt the text would be improved with the addition of short stories interspersed among the theory, his father agreed, and the pair rented a house in the country for three months to work on the book.

However, readers looking forward to more Ammaniti stories about kids may be disappointed.

'I'm bored by children now,' he says. 'Next month I'll start a new book, a love story.'