Vigil in a darkened room - Nadeem Aslam interview

THERE IS A HOUSE IN AFGHAN-istan where books – "the large ones as well as those that are no thicker than the walls of the human heart" – are nailed to the ceiling for safekeeping. Built by a master calligrapher and painter at the end of the 19th century, the walls of this house are covered with murals designed to enchant his beloved.

Each room depicts another of the five senses, culminating in a chamber under the eaves that is dedicated to love. Now those murals are hidden by mud, "as though all life had been returned to dust," in order to protect them from the Taleban.

Alongside the house sits a perfume factory, long abandoned. In the centre of its subterranean workshop, toppled, lies a giant Buddha's head. It was discovered when the builders excavated and they simply worked around it.

This is the home of Marcus Caldwell, an elderly English doctor who came to Afghanistan as a youth and never left. He married an Afghan – a fellow doctor – raised his daughter here, but lost both women, albeit in different ways, to the country's violent history. Crucially, it is here where much of the action of Nadeem Aslam's third novel, The Wasted Vigil, takes place.

Aslam, 42, is not merely slender, he's taut. This intensity is not unexpected. Eleven years elapsed between his acclaimed first novel, Season of the Rainbirds, and the award-winning follow-up, Maps for Lost Lovers. He spent great chunks of that time locked in a blacked-out room, writing the novel in longhand, crashing to sleep on the floor and waking to write again, wholly unaware of whether it was day or night, winter or summer.

Given the shorter lapse in time, we might presume that this novel was an easier labour, but that's not the case. Even as he finished his first novel, Aslam had two more in mind. It was, he said, "a case of eeny meeny," and the immigrant novel (Maps] won.

"I am an immigrant. I was born in Pakistan. I lived, still live, in those communities. I knew something was going wrong, though I didn't know that it would lead to 7/7. One noticed the radicalisation was occurring. Those boys who blew themselves up, boys like that were beating their sisters. We had that kind of radicalisation already, but it manifested differently.

"I also knew something was happening in Afghanistan. We in the West didn't know that because we walked away once the Soviets left. By 1993 thousands of people had already died and the consequences were there for the Afghan people immediately, but for us it took until 2001."

This, then, is really a companion piece to Maps for Lost Lovers. "When 9/11 happened, a lot of writers said, 'The book I'm writing is useless.' I said, 'Look, my book is on the (television] screen.' Even if there was no terrorism affecting the West the way it is now, even if we were unaware of Islamic radicalisation, I would still be writing these books. These things have been affecting the society I come from ever since I was born."

One of the inspirations for this book was Dostoyevsky's The Idiot. "In it, the detail about Russian life isn't as rich as it is in Crime and Punishment. He presented Russia as a question. I wanted to use Afghanistan as an animating principal, to show what the British involvement was, the American involvement, the Soviet involvement and the Pakistani involvement. Because let's face it, nobody out there is innocent. Everyone must take responsibility for what happened."

Hence the panoply of characters. There's Lara, a Russian, who's travelled to Afghanistan to find out what happened to her brother, sent there as a Soviet soldier some 25 years earlier and never heard from again. David, the American, is a former CIA operative who had a relationship with Marcus's daughter, Zameen, before she was killed by an Afghan warlord. Together with Marcus, he's searching for Zameen's son, the doctor's lost grandchild. There is Casa, a radicalised Afghan boy, and Dunia, a young Afghan teacher. These characters, and their various fates – not to mention actual events shaping the novel – were rooted in Aslam's mind the entire time he worked on Maps. "I had about 80 per cent of the storyline in place 15 years ago."

Still, why let the writing of these books consume his personal life to the negation of all else? Judging by his baffled look, Aslam thinks I'm spouting gibberish.

"It has to. I don't understand how it can't. I hope, when you read it, you felt you were in the presence of these vivid characters. That had to happen to me first, to be able to convey it to you. From September 2006 until May I did not see a single human being. I slept during the day, I wrote at night. I borrowed my brother's cottage and because they would be asleep at night when I was working I would leave messages on their answering machine to say I had run out of food. During the day, while I was asleep, my brother or sister-in-law would quietly come in and fill up the freezer. For seven months I did that. But I was not alone. I was in the presence of these characters."

Many authors not only write wonderful books but maintain families,other jobs and even social lives, I argue. He shrugs. "Maybe I've fallen into that habit. I think in that last stage I needed to be alone with the book – literally be alone and not even look out the window. I lived by electric light, more or less."

And then he says something intriguing and seemingly contradictory: "I hope that the end result manages to say something about the time we live in. There's a moment when Casa says that he's alone all the time and there are so many questions, and the girl says to him, those questions are being asked by everyone, there's no need to feel alone."

What lingered longest after closing the pages of this dense, profoundly sorrow-filled novel, was a host of sharply beautiful visual images, from the books and murals, to the Afghan habit of burying valuables in the yard for safety's sake, whether that was a grand piano or a television, necessitating trips outdoors, spade in hand, whenever you fancied using the thing.

"This is what people did," says Aslam, excitedly. "They buried their TVs – you had to. I didn't make that up. And the idea of the house with the five senses and love at the top; it can be seen as just a beautiful place but I wanted it to stand for the human body, which has been attacked. And I wanted the perfume factory to be the soul, alongside the body, and into the soul I drop the head of the Buddha." On its side. He smiles, nods. "On its side."

The book is not a tract, he insists. His primary goal is storytelling that engages the reader.

"I am always trying to find those – you know when we're on our own, humming a song? If you go immediately to listen to the actual song, you will notice that you sing it slightly faster than the singer does. Because the singer does not sing a sentence, the singer actually sings it a word at a time. The singer inhabits that word for the duration that he or she sings it, the voice does things with that word, and then he or she moves on to the next one. As a writer, the idea is always to find that tiny extra bit of time with each moment, to find its beauty and intelligence."

I'm not to worry, he reassures me. He has friends, a social life and, apparently, the most understanding and generous brother and sister-in-law alive.

"I'm very gregarious and I love being around people, but that's why I have to go away, as well. But I ask you, where would my characters come from if I didn't know so many different people?"

On researching The Wasted Vigil:

• "My book is the work of an outsider. There are a number of Afghan artists – film-makers, writers, poets, painters – doing great things that are much more culturally thorough."

• "I visited Afghanistan and talked to bread-makers, professors, students. Here in the UK, I talked to upwards of 200 Afghan refugees. Some, it has to be said, their legal status wasn't so good and they were frightened and nervous. I wanted to get a feel for what they thought had happened to their country, and the consequences for them."

• "The more I talked to them the more I realised I was enjoying the conversation. They'd say, 'That street in Kabul smells like these flowers,' and I went to Kabul and it did. It's extraordinary what you remember. Somebody else would say, 'The light in that street is what you have to know.' It was interesting approaching a place through someone's memory."

The Wasted Vigil by Nadeem Aslam is published on 3 September by Faber & Faber, priced 17.99. Nadeem Aslam is at the Edinburgh book festival tomorrow at 4pm.