No ordinary Roman Catholic nun, as she freely, even gleefully, concedes, the 81-year-old MacInnes is an accomplished classical musician and a prison activist in the mold of her American friend, Sister Helen Prejean, the Louisiana nun portrayed in the film "Dead Man Walking."

And unlike the unfair but still prevalent image of the brittle and stern nun clad in a severe black habit, Sister Elaine, as she's widely known, is quick with a hearty laugh as she wears slacks and sports a bright flower brooch.

The next part of her myth-busting requires a leap of faith. MacInnes is a Zen Buddhist roshi (master) - the first Canadian, among a few Westerners - and certainly the only Catholic nun to be invested into Zen's highest echelon.

Is the unusual combination a conflict in an era when the Catholic Church is caught up in a lot of soul-searching and house-cleaning?

Hardly, Sister Elaine chuckles in an interview in Toronto, where she shares a small house with six other members of Our Lady's Missionaries, an order of Roman Catholic nuns founded in Canada in 1949. If anything, she says, Zen has made her a better Catholic, and vice versa. She says Zen is a tool that has enriched her Christian spirituality without compromising it.

"The word 'spirit' means in Buddhism, as far as I can tell, pretty much what it means in Christianity: The presence of the sacred within," says MacInnes. "And that presence expresses itself in power. You can call it chi or qi, but it's power."

It also finds itself in the motto she's been fond of for years: Spirituality is what you do with the fires burning within.

Appropriate, then, that the maxim has morphed into the title of a new hour-long documentary on the life and work of the New Brunswick-born nun. "The Fires That Burn" premiered on Canadian television in December.

But it wasn't the film that brought MacInnes back to Canada in 2003 after spending 42 years abroad teaching yoga and Zen meditation to hard-core prisoners, with stunning success in Great Britain. It was mainly the decision to finally transplant her groundbreaking program to her native land.

The Toronto-based organization she leads, Freeing the Human Spirit, has won access to 20 prisons in Canada. It wasn't easy.

"I was told, 'You don't belong in our system because we are all faith communities. There's no place for you in the Canadian prison system,' " she recalls. "That got up my backbone. I just said, 'Well, I'll get in somewhere.' "

"There's also quite a bias against yoga. (Many consider) it the work of the devil."

Canadian prison officials, she says, even cited a biblical warning, from Matthew 12:45, that if you get rid of one devil, seven more will take its place.

"I'm not a trained theologian or biblical scholar," MacInnes says patiently, "but I know from my own experience that's not what happens."

Her program teaches yoga postures only (the asanas) and a simple type of meditation in prison because she says many people - in the general population as well as in prison - are too physically and psychologically unhealthy to deal with the rigors of Zen.

"It takes people to a deeper state of consciousness, and psychologically they are ill at ease in that area," she says. "That has to be seen to first."

And she was "aghast" at the physical condition of some prisoners. "Some of their bodies looked like bags of potatoes. You'll never get any spirit there."

Still, the program has a proven track record of helping improve inmates' concentration and self-esteem.

"The alienation many prisoners have just drops away. It's a wonderful moment for them."

Born in Moncton, New Brunswick, in 1924, MacInnes graduated with a degree in violin from Mount Allison University, studied at Juilliard in New York City and taught at the Mount Royal College Conservatory in Calgary, where she also played professionally with the local symphony.

Her hands are now gnarled but strong - testament to her piano degree from Toronto's famed Royal Conservatory of Music.

At the relatively advanced age of 30, she joined Our Lady's Missionaries, followed by five years in a convent in Ontario. In 1961, the nun was assigned to Japan to teach music and English and baptize as many Japanese as possible. Instead, she discovered the stillness and austerity of Zen.

"I started Zen to know the Japanese people better but I continued it as a personal discipline in the development of my own spirituality, and finally chose it as my service to others," she says.

She even lived with Buddhist nuns in Kyoto for a time, engaging in a samurai-like regimen of 10 hours of sitting meditation (zazen) a day.

It was in the Philippines, where she was dispatched in 1976 to pursue an apostolate in animal husbandry, that MacInnes got the idea to impart Zen's calming influence to prisoners.

Her first breakthrough was at the Muntin Lupa facility outside Manila, a "hellhole" where 10,000 nearly naked prisoners sat in filthy individual cages. At the Bago Bantay detention center in Quezon City, she worked with 10 political prisoners who had been tortured, and saw firsthand their transformation from angry and tense to relaxed and energized.

Her reputation drew her, at the age of 69, to Oxford, England, and the directorship of Britain's renowned Phoenix Prison Trust. The trust was an outgrowth of the Prison-Ashram Project, founded in 1973 by American psychologist Ram Dass and activist Bo Lozoff, who came up with the idea of helping inmates see their cells as monasteries.

MacInnes organized meditation workshops in 86 prisons throughout the U.K. She personally led five sessions with high-ranking members of the Irish Republican Army at the Maze Prison, and saw hundreds of hardened murderers, sex offenders and drug addicts experience what she calls "the silence of heaven."

Authorities noticed drops in inmates' tension, improvements in their concentration and sociability, and ultimately, reduced prison violence. As Andrew Coyne, former governor of the Brixton Prison, says in the documentary, the program now operates in half of Britain's prisons and demand for meditation classes is enormous.

In 1980, the famous Zen master Yamada Koun Roshi invested MacInnes into the rarefied stratum of roshi (literally, "old teacher") - the top rung.

There are perhaps 100 roshis on the planet. The Zen name she was given - Ko Un Ang - means, roughly, "Light and Cloud of a Small Hermitage."

MacInnes says she receives no flak from Catholic higher-ups for embracing another religion. "Thank God they've kept silent," she says with a laugh.