Roddy Doyle: 'I wanted to ask the questions before it was too late'

Right at the start of Roddy Doyle's first novel, The Commitments – before the start, in fact – the reader is informed that "This book is dedicated to my mother and father". Underneath is the dictum of Joey The Lips Fagan, the mendacious, superannuated trumpeter who is one of its most memorable characters: "Honour thy parents, Brothers and Sisters. They were hip to the groove too once you know. Parents are soul."

Keeping that in mind, it is plain that Doyle's latest book, his first excursion into non-fiction, is not so much a new departure as a return to first principles. Rory and Ita (Jonathan Cape, £14.99) is a biography of his parents: an increasingly familiar sub-genre, but one to which Doyle gives a refreshing twist (unlike, say, Blake Morrison) by getting his subjects' full co-operation and approval. The result is a moving and delightful book, one which manages the extraordinary trick of being both scrupulously realistic and deeply sentimental.

Doyle's motives for writing the book probably don't require much explanation beyond the one he offers in a brief foreword: "I wanted to ask the questions before it was too late." It is a common enough thought, as he has found. "When I started telling people about this," he says, "virtually everybody says, 'Oh, I wish I'd spoken to my parents,' or, 'I wish I could do that.' "

Although it started as a purely personal project – taking his parents into the kitchen, one at a time, and recording their answers to his questions – the possibilities for a book soon became clear as he listened to their different, and occasionally contradictory, versions of events.

At the time, too, RTE was showing a seven-part documentary series on Irish history, each episode devoted to a decade of the Irish state: "I'd forgotten really what a new country Ireland is. My father was born the year after the state was founded, and as I listened to both my mother and my father I felt that not only were they telling me about themselves, they were actually telling me about Ireland and about how it's changed."

If anything, he rather undersells the book's resonance. Rory and Ita's story is not only the story of a nation, but the story of the lurch into modernity that the whole world underwent in the 20th century. There can be few readers anywhere who won't find some echoes in their own family history.

The decision to interview them separately gave the book what feels like a natural shape (though he says that finding the structure was hard). His parents take it in turns to recall different periods, so that to begin with their stories run in parallel. There are occasional overlaps as they recall, say, the Eucharistic Congress of June 1932, when huge crowds attended an open-air mass in Phoenix Park; but the interest lies largely in the contrast between their lives.

Ita grew up in a small middle-class household in the suburbs of Dublin. Her father was a civil servant, and her mother died when she was four: a fact that overshadows the whole book, darkening it. Rory's family was larger and poorer – his father a tram-driver – and although they started out in Dublin, just a few streets from Ita, later they moved a few miles out to the more rural environs of Tallaght.

After Rory and Ita meet and their stories converge, the interest comes from their sometimes outright contradictory views. Doyle was careful to let them hear and comment on each other's narratives, and their qualifications and alternative versions are sometimes given in footnotes.

What makes Rory and Ita particularly rich are the differences not simply in content but in style of memory. Rory has a gift for anecdote, the nicely rounded comic story. Ita, on the other hand, has an unusual grip on sensuous detail: the look and feel of an item of clothing, the pattern of the lino on the floor when she was a child. Past events, including past tragedies, seem to have a special glow for her.

So Rory recollects the financial ins-and-outs of buying their first car, and the retrospectively comic horrors of driving untutored and untested: he had had one half-hour driving lesson from his sister's husband. Underneath, Ita says in a footnote that she will "never forget the gorgeous leather smell inside it. It was beautiful, it was wonderful; we were made for life."

Roddy interpolates a few notes fleshing out Irish history. He also sub-edited their stories, changing the odd word to avoid repetitiveness, and sometimes taking a paragraph out of one day's transcript and putting it with another – though never without asking their permission.

To begin with, he had some trouble suppressing an urge to edit, and editorialise. For instance: "I suppose, the politically correct, vaguely left-wing man in me would have preferred my father to be more hostile about his Christian Brothers schooling. But he wasn't, and that was fair enough. I had to kick myself, and say, 'Now grow up and accept his version here. Don't try and impose your own more trendy version on it.' " This was especially difficult, because "These days in Ireland, you feel a bit left out if you haven't been sexually abused by a priest or a Christian Brother."

He was surprised, too, when his mother couldn't remember anything about his father proposing to her, and neither of them could remember saying "I do" at the wedding. "The writer in me said, 'Oh, no.' And then actually, the better writer in me said, 'Oh, yes, this is far more interesting.' "

He had only one row with them, very early on, "about a piece of information that I found fascinating, because it told me as much as I would need to know about the difference between Ireland way back then and Ireland now. I thought really, almost as a kind of metaphor, it was terrific. But when it came to seeing it in cold print, if you like, even though it was just an A4 sheet of paper, they weren't happy." Unfortunately, he can't even hint what that piece of information was.

By strictly academic or journalistic standards, the book's unwillingness to challenge the parents' versions is a failing. The advantage is that Rory and Ita becomes a fascinating study of the way that memories displace solid facts; indeed, memories become facts, to all intents and purposes.

And it is possible for readers to speculate about the facts given. For example, Ita's father, Jim Bolger, was deeply involved with the IRA during the war of independence. Ita insists, "He never fought, as such. He was more an intellectual than a fighter." This begs the question of why his first job in the newly independent state was sitting outside the office of the new Minister for External Affairs holding a gun. Surely, you think, they must have had good reason to think he knew what he was about.

The book also mimics the structure of memory in the way it accelerates as Rory and Ita grow older. Childhood and youth take several chapters for each; the last 30 years are skipped over in a few paragraphs. Partly that is because Doyle, out of a combination of deference to his brother and sisters and modesty, keeps their childhoods out of it (his own birth is consigned to a footnote).

All the same, there are some hints as to the roots of his fiction. Like Henry Smart in A Star Called Henry, Roddy was named after an older brother who died – another of the bleak facts that give the book emotional intensity. Unlike Henry, Roddy never felt any resentment: "But I suppose I was curious, because I often wondered then, well, if he had lived, who would I be?"

While he recalls from his own childhood some of the terrors and viciousness the hero suffers in Paddy Clarke Ha Ha Ha, his home life was harmonious: "I won't for a minute say that there was never any raised voices in our house, but I don't remember a serious argument between my parents. I certainly don't remember, I never saw, violence, and I doubt very much if there was any. It was generally a very happy place: full of people, talking, talking, talking, talking, talking." In Rory and Ita, we get to join in the conversation. It's a privilege.

Roddy Doyle: biography

Roddy Doyle was born in Dublin in 1958. After a Christian Brothers school and University College Dublin, he became a teacher. His first novel, The Commitments, was self-published in 1987, and sold to a British publisher in 1988. His other novels are: The Snapper (1990); The Van, shortlisted for the 1991 Booker Prize; Paddy Clarke Ha Ha Ha, which won the 1993 Booker Prize; The Woman Who Walked Into Doors (1996); and A Star Called Henry (1999), the first part of a series. His children's book, The Giggler Treatment, came out in 2000; the sequel, Rover Saves Christmas (2001), is being developed for the screen. Doyle has written or co-written screenplays for films of The Commitments (1991), The Snapper (1993) and The Van (1996), as well as an original screenplay, When Brendan Met Trudy (2000), and stage plays. He and his wife have three children and live in Dublin.