It is the definitive literary challenge, the task of following a superb debut volume of masterly, grotesque, controlled short stories with an equally original first novel. Mike McCormack, author of Getting It In The Head (1996) which won the Rooney Prize for Literature, was faced with exactly that. It is difficult to know whether to sympathise or simply be envious. He is the first to admit that writing his second book proved every bit as torturous as it is supposed to be - in fact, more so. Crowe's Requiem, even by the standards of literary long hauls, has had a tough birth.

"There were times when I lost faith, everyone did. Even my publishers had got fed up with it," he says. Now that it has finally arrived, he seems relieved rather than triumphant. "I think there's some great stuff in it, but . . . " That "but" says a lot, as much about McCormack the maturing writer as his book.

Experiencing struggle has been useful for him. The critical reaction to Getting It In The Head was outstanding and justified, enough to burden any young writer for a long time. The battle to make his new book work contrasted with the ease of writing those astonishing stories. It also highlighted the different narrative demands of a novel. "With stories, you know when the end comes. A novel, well . . . " he pauses, "it's a longer journey."

The most obvious difference between the two books is the vulnerability of Crowe as a character and also as a narrative voice compared with the surreal father-killers and bomb-making juvenile delinquents featured in the short stories. The eponymous young narrator of Crowe's Requiem is a romantic hero embarked on a quest for love which will kill him. Surreal flourishes are still in evidence but this is a gentler, more compassionate work.

Indeed even the prose has a diffidence, noticeably unlike the linguistic bravado and unsettling observations which elevated several of the stories well beyond their plots. "I wanted to make it a book from the heart. Getting It In The Head was exactly what it says - it was all in the head. It's a book to be read at arm's length.

This time I wanted to engage the emotions, it's a lot harder to do," he says, showing some surprise.

McCormack is 33, but in both appearance and demeanour seems years younger. His soft Mayo accent and earnest, bespectacled, boy's face could belong to a hopeful in the Young Scientist Exhibition, explaining his project. His facial expressions change almost as quickly as the western sky. On the way to the interview he had bought two books. Displaying his new copy of the great American experimentalist Donald Barthelme's Forty Stories, he says matter-of-factly: "I absolutely love his work, he's a genius." Holding up his other purchase, Ice, by the enigmatic English author Anna Kavan, he asks: "What do you think of this?"

Such is the ease and almost aggressive fluency of his stories with their black, horrific twists and turns, that McCormack's affable, benignly confident personality appears a contradiction. When it comes to graphic description of dismemberment, it is clear he learned a lot from a time as a butcher's assistant. He smiles and admits to having become accustomed to friends and strangers alike remarking to him: "You're one sick bastard." He laughs slightly manically.

Violence and dark obsessions dominate his stories and even the gentle Crowe remarks of himself: "Throughout my teens I remained a glowering presence, who stuck by choice to the back of the class. By then I saw myself as a kind of warlock's apprentice, a keeper of secrets laid down in no curriculum, recognised or otherwise." The narrator's fate is decided early on. "He knows his heart is his weakness, that he will die by his heart," says McCormack, and agrees that the narrative is dictated by the relentless inevitability of Crowe's passage to a death which could be either the ultimate romantic gesture or the only way to escape the demands of love.

The first person narrative has, to date, proved his surest voice. "I just feel confident in it, but that doesn't mean I wouldn't try another one. But, for the moment, it's where I'm at."

As with any writer who moves to the novel form after having successfully worked within the short story genre, McCormack was faced not only with the challenge of sustaining a narrative, but of bringing the same characters on a longer journey. In this case there was not only Crowe, his narrator, but also Marie, an odd young woman who becomes the narrator's love object. "She is very important for me, as she is my first female character." Her characterisation is, however, one of the weaker elements in the book.

Born in London in 1965, McCormack grew up in Louisburgh, Co Mayo, aside from a couple of years back in London between the ages of four and five. He and two brothers and sisters were raised by his mother. "I went to the local secondary school, it was the first co-ed in Ireland." Initially studying electronic engineering at the Regional Technical College, he abandoned the course after a year. "I gave it up," he says with a chopping gesture, as if he just cut it off from his life.

Then he worked as a gardener, enjoying the freedom of it. "It was the only well-paid job I ever had."

In common with his character Crowe, McCormack also attempted to secure work - and a fat fee - as a human guinea pig in medical experiments. It was in Germany. Physical condition was a factor. "I didn't even get past the pre-trial test."

On retiring from gardening, he was ready to return to full-time education and studied English and philosophy at University College Galway. He began an MA in philosophy and set out to write a thesis on Heidegger. Interested enough to enjoy reading the German existentialist, he never completed the dissertation, as he had become distracted by writing stories. "I was living in a little room. By the time I should have handed in the thesis, I'd half the stories finished."

Unlike many writers, who have secured agents before being published, McCormack sent his stories to agents who returned them, with a cover note announcing: "Books of short stories don't sell." Having made four copies of that first book, he decided to go without an agent's support and sent it to "20 or 30 publishers - well, it went to some twice and was rejected by most of them twice." Cape (his publishers) rejected it the first time round as well. But then Robin Robertson (the Scottish poet and publisher) came to Cape and he does his own reading - "he doesn't use professional outside readers, like most of the publishers do."

Robertson liked it. "But he said there was no point in taking it on unless I had something else. So I polished up the 20 or 30 pages of my novel. And there was nothing for about three months. Total silence. it was terrible." McCormack enjoys recalling the day he marched to a phone box in Eyre Square to call Robertson. The timing was remarkable. Robertson replied that he had just written to him. "He said he was going to buy my two books, I went wild." As Robertson was due to come to Ireland with another Cape author, the Michigan poet, essayist and undertaker Thomas Lynch, whose ancestors came from Co Clare, McCormack would be signing his contracts in person. "On the day I was to sign I met Thomas Lynch.

We shook hands and he asked me: `Do you have a place to write? There's a house in Clare that's empty for a lot of the year.' A place to write, as simple as that." There is a strong sense of a slightly lop-sided, surreal Ireland at odds with the tensions of human relationships, particularly father/son and son/father dynamics through his stories. "On the very evening I burned down the left wing of our house my father told me he hated me," begins The Terms. But he says he only noticed this recurring theme when it was pointed out to him. In Crowe's Requiem, the father figure is replaced by a larger-than-life grandfather, who appears doomed to immortality, only to abruptly fade. McCormack had had no difficulty with his own father, who died young.

But there is so much more to the apparent violence in McCormack's fiction. Even at its most extreme, there is always a thinking individual attempting to make sense of life, of himself. Consider a story such as Thomas Crumlesh - narrated with the lucidity exclusive to madmen, it looks at the artist as obsessive, but it is also a moving account of friendship and utter loyalty. Readers have already been informing McCormack that the west of Ireland dominates the new book. However, as in his stories, even when at their most overtly Irish, there is also a marked affinity with central and eastern European literature about McCormack's fictional hells, particularly in the case of Crowe's Requiem. His face lights up. "I wrote a lot of it in Romania. I'd gone to Timosoara where so much of the terrible things had happened under Ceausescu. You know, it was doing the old thing, becoming yet another in the long line of writers living in cheap hotels trying to make a book work."

Crowe's Requiem is published this week by Jonathan Cape at £9.99.