TORONTO -- Oscar-winning writer John Irving's new novel, "Avenue of Mysteries," began over 25 years ago with a screenplay, a trip to a circus in India and an obsessive fear of something happening to children.

The newly published book follows Juan Diego, a Mexican wunderkind and "cripple" who teaches himself to read and write in multiple languages while living in a poor colony for families who work at a dog-infested dump.

His feisty younger sister, Lupe, has a speech impediment, a clairvoyant mind and a passion for the Virgin of Guadalupe.

The book flips back and forth between two time elements. In one, the teenage siblings traverse the worlds of Jesuit priests, an orphanage and a circus. In another, 54-year-old Juan Diego is an Iowa writer who goes to the Philippines to fulfil a promise he'd made to a Vietnam War dodger as a teen.

Irving, who won an Oscar in 2000 for writing "The Cider House Rules," says he often begins his sweeping stories in screenplay form. And he often gathers notes for possible novels over a period of many years before he writes them into a complete story (he won't do so unless he knows how it ends).

Such was the case with "Avenue of Mysteries," which marks the longest period of time he's ever developed a story.

The inspiration came in the 1980s, after Irving blew away the literary world with his bestseller "The World According to Garp."

He was living in New York and saw photographs of child performers in an Indian circus taken by the late photographer Mary Ellen Mark, a friend who was married to director Martin Bell.

"She showed me these pictures because she and Martin thought, 'Maybe John would be interested in writing a screenplay about such children at risk, since kids at risk is kind of his thing,"' said Irving, who's written about the subject in many of his books.

"Well, I saw these photographs and I was attracted to them in a narrative way, appalled by them in other ways.

"By the time I went with Martin and Mary Ellen to India in the winter of 1990, I had already written several drafts of the screenplay called 'Escaping Maharashtra."'

The three lived in the north of India for a while as Irving crafted a story about two downtrodden children at risk in the circus.

But they couldn't get the film made, because the board of censors there disapproved "at foreign-made films that cast India in a less-than-favourable light," said Irving.

The story was revived years later, when Mark showed Irving her photographs of children in circuses in Mexico.

He and Bell travelled to Mexico multiple times for another potential screenplay, visiting all of the sites that are described in "Avenue of Mysteries."

Irving realized the story would work better as a novel when he decided to also look at Juan Diego as a retiree reflecting on his childhood. The character is in a medication-fuelled haze that has him wondering if he's dying.

That element of the story took Irving to the Philippines.

"For all the life of imagining I've spent, I never had taken a trip quite like this before," the 73-year-old American author said in his Toronto office, where his Oscar sits on a mantle in a light-filled workspace filled with photos, including those of the aforementioned circus children.

"Because I went with my notebook, taking notes, but all the while I was there I wasn't thinking about what I saw. I was imagining that I was Juan Diego at 54."

Irving didn't visit the site of the final scene in the story -- of Juan Diego in a church -- until just before he returned home.

"It's not a very well-veiled homage to 'Death in Venice,' frankly," he said of "Avenue of Mysteries."

"My sense of Juan Diego as my homage to Gustav von Aschenbach is pretty clear. And in fact, (naming it) 'Death in Manila' would have been a pretty clear way to say to (Thomas) Mann, 'I've always admired that novel."'

About a third of Irving's novels have writers as main characters, but Irving said "it's simply erroneous" to think of him as a fiction writer who mines autobiographical material.

"My oldest son once said very smartly that the most autobiographical thing about me in my novels is that I write about what I'm afraid of, and he's right," he said.

"The most autobiographical thing in my novels has nothing to do with whatever has happened to me. It has a lot to do with what I hope never happens to me or especially to anyone I love.

"My novels are largely 'what if' disaster stories."