The recurrent motif of Colum McCann’s seventh book, Let the Great World Spin, is Philippe Petit, who entranced the world with his extraordinary high-wire walk between the Twin Towers in 1974. The novel explores the interconnecting lives of eight New Yorkers, all of whom are in the city on the August day Petit walks through the air 110 storeys above them. In between their stories, McCann returns to Petit’s tightrope walk, as he wondrously skips, balances on one leg and even lies down, while the thousands gathered beneath collectively will him not to fall. Twenty-seven years later, aghast millions would be watching live on television as people fell from the buildings before the towers themselves collapsed.

McCann has been living in New York for many years now. When I meet him, he’s back briefly in Dublin, the city where he was born, as part of a lengthy US and European book-promotion tour. The new novel has already been translated into French, German, Spanish and Italian.

“The book is a pretty straightforward 9/11 allegory,” he explains. Although he had been thinking about a book that would deal with the subject in some way since 2001, he didn’t start it for years. Instead, he wrote Zoli, a novel about Slovakian gypsies, which he dismisses now by describing as “a mess and a failure”.

On September 11th 2001, McCann’s father-in-law, Roger Hawke, was working on floor 59 of North Tower, the first one to be hit. Profoundly shocked and dazed, he made it down the stairs, and uptown to the apartment where McCann and his family were living. He was covered in ash. McCann’s four-year-old daughter, Isabella, jumped into his arms “and then she recoiled”, McCann relates, suddenly speaking extremely quickly and with intensity, “because she could smell the smoke and she thought he was burning, because of that peculiar smell from his clothes. And I suppose my question was, as everyone’s question was: how do you write about this? I never questioned the desire to write about it, nor the correctness of wanting to write about it, which I’ve done with other things I’ve written about. But I was there. It’s my city now and I don’t think people should or shouldn’t write about it, but I felt a deep need to confront how I felt about what happened at that time. I wrote about it; I wrote articles about it. But how do you write fiction about it?”

McCann still recalls details about that time. For days, dust permeated the streets of Manhattan.

“Nothing was free of the influence of meaning at that particular time,” he says. “You’d go down to the shops and you’d look at shelves full of medicines, and then there’d be a huge gap on the shelf, where all the eyewash was gone. Or you’d see dogs wandering around on their own. I’d never seen that before in Manhattan. Every dog has an owner.”

What came to him first as a way into the novel was the subversive image of Petit balancing in mid-air between two buildings that seemed to be such solid, trenchant parts of the landscape. He had no idea until a year ago that the documentary Man on Wire was going to come out, but it didn’t bother him.

“Who owns a story?” he asks rhetorically. “When we go back and look at fiction in, say, 20 years from now, the iconic image of the falling man is going to be enormous, how that penetrated our consciousness.

“I don’t think I can say anything about 9/11 or New York that hasn’t been said. What I do think I can do is allow emotional access to certain landscapes that other fiction won’t necessarily get at.”

McCann sees his job as a novelist as being “to inhabit those little dusty corners that nobody else is necessarily going to value on the six o’clock news”. The characters in Let the Great World Spin who live in those neglected dusty corners include a hooker and her drug-addicted daughter, and a woman who has lost her sons to the Vietnam war.

There is also an Irish emigrant who is a St Francis-type character, giving away all his possessions and living in poverty in a South Bronx housing project.

“Hopefully the book will emotionally engage you on such a level that your world gets shifted sideways for a little moment and then you will look at things in a slightly different way,” McCann says. There is a coda at the end of the book, set in October 2006, where all the characters’ stories fuse together in varying ways. In 1974, the war the world was watching was in Vietnam. By 2006, global attention was on Iraq, in the final years of the Bush presidency. In the coda, there are moments of hard-won redemption for some of the characters.

“The last chapter is an Obama metaphor for me,” McCann says. “Things turned. The narrative turns. It’s open-ended.”

McCann does a considerable amount of research for all his books, which frequently involves travel. Let The Great World Spin was, he says, “the easiest book to research and write because I was there, in New York. But what really knocked the stuffing out of me, and still has to this day, is the passion I felt writing it.”

He pauses, thinks, corrects himself doubtfully. “That’s a silly word to use: ‘passion’. But I spent up an awful lot of emotion in this book,” he says.

So, as a novelist, has McCann said everything he wanted to about 9/11? “I thought I’d said everything I wanted to, but I might go back in,” he confesses. “If I went back in, though, I’d go back in on the day itself.”

Does he consider this to be his best book? He delivers his answer confidently. “Yeah. I think so. I think so.”

Although the Washington Post disliked the book - “His theme is stale, and the exhaustive back stories he gives each character never pay off” - the novel has received several excellent reviews in the US, where it was published earlier this summer. The New York Times reviewer described it as “one of the most electric, profound novels I have read in years” and “like a great pitcher in his prime, McCann is constantly changing speeds, adopting different voices, tones and narrative styles as he shifts between story lines”.

Despite the enthusiastic reviews, and being widely tipped for the Booker longlist, Let the Great World Spin did not make it on to the list. Was he disappointed?

There’s a short silence and a small, unmistakable sigh. “Yeah, I was upset,” he admits frankly, shrugging. “You’re the first person to ask me that. I would have loved to have been on it. I’ve never got near the list. But it’s not an Olympics, nobody gets the gold medal. In certain pursuits, other people get the gold medal, but when we’re talking about literature, certain people will get on certain lists and certain people won’t get on others, and obviously this one didn’t make it.

“I won’t lie to you and say, oh, it didn’t bother me whatsoever. It took about an hour or two, and then I went ‘oh well’. And it was in the New York Times bestseller list last week, which is nice. Which is more than nice.”

Later in the interview, he returns to the subject again. “I don’t want to dwell on it, but I do want to get it right,” he says, frowning and staring into the middle distance as he searches for words. “I think the longlist is a really good list and fair play to wherever the Booker goes, and to whomever it goes to. But the idea that we would make it the be-all and end-all of literary prizes could, I think, be damaging in general. It’s not a sprint.

“Can we universally say what’s the best book or the best poem? I know people make lists all the time, but time takes care of things too.”

Reading History: 9/11 Novels:In the immediate aftermath of September 11th 2001 there was a temporary stunned silence from the literary world, before a spate of novels addressing 9/11 began in 2005 with Extremely Loud and Incredibly Close, by Jonathan Safran Foer. The following year saw the publication of The Good Life, by Jay McInerney, The Emperor&'146;s Children, by Claire Messud, and Terrorist, by John Updike. Falling Man, by Don DeLillo, appeared in 2007, followed last year by Jospeh O&146;Neill&146;s Netherland.