IN THE tiny townland of Moyne, deep in south Wicklow, a 51-yearold man is sitting outside in the sun, nursing a cold cup of coffee and letting the fact of being on the shortlist for the 100,000-worth Impac literary award sink in.

"There's a real childish feeling about it, " says Sebastian Barry. "I don't know if I've taken it in yet. It really clears out the head and puts a spring in your step. . . Maybe in slightly grander circles one should be more cynical about it, but it really hits you in a primal way."

His 2005 novel, A Long, Long Way , has already taken him around the world, and onto a previous shortlist, that of the Man Booker Prize. He "was not disappointed at all" by not winning the Booker.

"The longlist was great fun, the shortlist was f***ing miraculous.

It's as much fun as you can have as a writer."

The cover of A Long, Long Way is emblazoned on banners all along Dublin's O'Connell Street, as part of the City Council's 'One City: One Book' initiative, which aims to encourage everyone in the city to read the novel this month. Barry marvels at the life the book has had. And, above all, it means "a lot more people [are] going to read about Willie".

Willie is the son of the chief super of the Dublin Metropolitan Police, Thomas Dunne (who was the subject of his play The Steward of Christendom). In an earlier novel about the daughter in the family, Annie Dunne, Willie went off to fight with the Royal Dublin Fusiliers in Flanders. When Barry's editor said he would like to publish a novel about the Irish in the first world war, Barry thought he might follow Willie to the Front.

"That's the moment of naivety, " he says. "The more I read about it, the more grotesque it is. Nobody really knew what was going on. It was an enormous confusion, a sort of viral event in the body of Europe. In the first 15 minutes of the Somme, 50,000 people were killed."

A Long, Long Way does not spare the reader the details of those deaths. Barry had "a very strange sense of being allowed into the trench" with the men he wrote about, "so that when I was seeing and hearing the horrors, [I had] a responsibility to them to be as accurate as I could be. . .

"I was terribly upset every time somebody didn't make it through.

It was visceral, and intensely real.

"Even if you signed up as a volunteer, you couldn't leave till the war was over. That was what it felt like [for me]. I had signed up to do it, so I was going to have to do it.

And what got me through, and what made it, bizarrely, an intensely enjoyable and invigorating book to write, was the men, just the men.

"I was careful to put people into that platoon that I knew in my life, that I valued in my life."

One of the key figures is Christy Moran, a laconic, shrewd, but gentle sergeant from Kingstown, who walks with Willie through the war. The inspiration for Moran was Barry's builder: for two years, Barry worked for him . . . while paying him . . . as they built a family home out of the crumbling old rectory in Moyne that Barry had bought with his wife, Ali.

"As a writer, you don't spend a lot of time with groups of men. It was wonderful to work with people, back-breaking work.

They'd see you nearly weeping, in a trench, pipe-laying, and they'd make a joke to lighten it.

"The company of builders is the finest company you can have. I wouldn't be able to write the book without having had the experience of working with those men.

Builders are very like soldiers, doing a really, really hard dirty job sometimes."

Some 200,000 men from the island of Ireland fought in the Great War, yet, south of the border, they were largely forgotten. After the 1920s it wasn't so much talked about. There was a 60-to-70-year gap in the conversation." This is why the Great War today "feels so immediate", he thinks. "It feels like Vietnam when you talk about it."

He has been doing readings around the world for two years, and the reaction is always the same, he says, tangible and immediate.

People write to him . . . he quotes one letter, from a Vietnam vet: "I am that 18-year-old that turned into an old man carrying the stretchers of his comrades in Laos."

"Every last man of those 200,000 . . . even those who survived and lived long lives . . . is dead.

They're all gone. It would be an absolute imposition on their memory for me to say that the book is anything to do with those 'real' men, but there is a part of me that hopes that their sleeping hearts are glad in some way, because [with the shortlisting] their story disseminates."

For him personally, being nominated "adds to the pleasure of sitting out in your chair and listening to the birds sing", he says.

"It's sort of 'good weather'. But when the winter comes, I'll just light the firef" Barry knows what it is like when the winter comes.

His 2002 play Hinterland was seen as a crass intrusion into the private affairs of the Haughey family and provoked a massive negative reaction. "I have learned over the years to accept the catastrophes with the other stuff. . .

There's something about disaster that it just diminishes you in a good way. It cuts you down and makes you, for a brief term, less stupid and more at ease in the world.

"The Hinterland thing did force me very much to think again about what writing was, and what it was for. It's like that moment when you see the farmers burning the field.

And the field looks completely black and destroyed. But in fact it's a preparation for the next thing.

"That is the arena you're in.

When a boxer goes into the ring he risks having his brains knocked out. We risk more arcane things.

"I always think of it as the stepping stones across a very stormy isthmus, and all you have is these poxy Victorian stepping stones to get you across, almost decorative stones. And you can't skip any of them because you're immediately in the briney, and you've got to go on to each one as it comes to you. How could you write for 27 years and not meet such a thing?"

Curiously, he remembers the day after Hinterland opened on the West End, with London "pullulating with terrible reviews" as "one of the happiest days in my life".

Failure was "very simplifying". "It's like being dead and waking up the next day and the sun is shining."

By contrast, the massive success of The Steward of Christendom was "a sort of catastrophe in many ways. It took us out of our lives. We earned some money for the first time, we moved out of our house . . .

we moved three times . . . we shifted around.

"It's like when people say to you, 'What wonderful babies!' and you think, 'What wonderful babies?

They've ruined my life! All I am now is the nappy changer.' You just don't have the perspective on it . . .

it's afterwards that you realise.

And then afterwards, you get some sleep, and you fall so deeply in love with them.

"You're writing and writing and writing and you're looking into things and you're doing it to stay alive and you're doing it to honour life and you're doing it to interrogate your own loved country, all those things, all those reasons you write, and then everything opens up like a box that was so hidden and screwed down tight that you didn't even know it was there. That's success; you've got to cope with that."

We are sitting now in the anteroom to his study. A wall of bookshelves, and others in small stacks in corners, a fire crackling, the thin March sun filtering in through the window. It is idyllic, apart from the telephone that keeps ringing in his study. It rings off, and then a phone at the other end of the house rings. He pauses to think who it might be, then waves the ringing away with his hand. We talk on. The phones ring again, in choreographed sequence.

He waves them away. We talk on.

Gently, the interview winds towards its natural end. The phones ring again. He does a mental namecheck: can't think of anything important it could be.

The phones ring out. "What time is it?" he asks. Then there is a flash of fear in his eyes. "Is it half three?"

He is on school-lift duty. His 14year-old twins finish school at 3.30 in a village 20 minutes away. It is past four. Panic, pandemonium.

Minutes later we are in the Volvo estate, youngest son, Toby, in the back. Does he do this often, I ask Toby.

"Yes."

So what's it like having a writer for a dad?

"It's kinda normal."

Back at the rectory, the sun now low across the valley, filtering through the branches of the beech trees, we sit in his favourite chairs, outside the kitchen. The two dogs, tall, lean poodles, one black, one white, sniff at the stranger. He talks some more, gently, ruminating, over the racket made by the rooks in the trees. "We're always trying to explain ourselves to ourselves."

Metaphors introduced into the conversation earlier wind their way back in, sometimes obscurely.

Talk of crossing his "stormy isthmus", of naivety and innocence and heroism, of his astonishment at the magnanimity and courage shown by Northern Ireland's leaders, of the joys of parenting, of the quiet of south Wicklow.

And then it is time to leave. I drive up the laneway, past the old churchyard, and Barry stands at the door for a moment, surveying the hinterland.

Eight novels vie for /100,000 prize

Of 138 nominations, eight novels have made the shortlist for the IMPAC Dublin Literary Award. Lord Mayor, Cllr Vincent Jackson announces the winner in City Hall on 14 June. The award of 100,000 . . . won by Colm Toibin last year for his novel The Master . . . is the world's biggest prize for a single work of fiction.

And the nominees are: A Long Long Way by Sebastian Barry: profoundly moving story of Willie Dunne, an Irishman fighting in the blood-soaked trenches of the First World War but caught in a no man's land of allegiance.

Arthur and George by Julian Barnes:

The events of a century ago resonate vividly for today as the themes of identity, race, nationality, guilt, innocence and decency are all examined in the case of George Edjali, a half-Indian solicitor wrongfully imprisoned.

Extremely Loud and Incredibly Close by Jonathan Safra Foer: the story of nineyear-old Oskar Schell, drawn down a personal journey of discovery following the death of his father in the 9-11 attacks.

Slow Man by JM Coetzee: Photographer Paul Rayment loses a leg in an accident and, as he struggles to maintain his independence, changes his perspective on life, love, home and mortality.

No Country For Old Men by Cormac McCarthy: The king of the contemporary western finds elemental truths in an unchanging landscape along the TexasMexico border.

Our Stealing Horses by Per Petterson:

Memories of a summer when he was 15 which will change forever the life of the narrator Trond, now 67, beautifully told by Norway's greatest writer.

Shalimar the Clown by Salman Rushdie: Rushdie's great talent for weaving intricate tales are realised in this epic of murder, personal passion and terrorism.

The Short Day Dying by Peter Hobbs:

A debut treatise on faith, love, nature and spirituality in this story of a young Methodist blacksmith who falls in love with a blind girl.