The woman who answers the phone at Carol Shields’ house has so light and clear a voice you think it belongs to one of the author’s four daughters. But Shields herself is speaking. And however young she sounds, she does not pretend to have the luck of time.

The 66-year-old fiction writer, winner of the Pulitzer Prize for “The Stone Diaries,” was diagnosed four years ago with breast cancer, and a mastectomy, chemotherapy and radiation did not prevent the disease from spreading.

Now terminally ill, she expects her new novel, “Unless,” to be her last. Her book “tour” is largely confined to her home in Victoria, British Columbia.

“I felt I owed my publisher something, and the phone is the best way to do it,” Shields says when asked why she agreed to do interviews.

A native of Oak Park, Ill., Shields has lived more than 40 years in Canada and writers there are paying tribute while she is still alive. At a recent gathering in Toronto, Margaret Atwood, Michael Ondaatje and others praised both Shields and her books, with Ondaatje calling “The Stone Diaries” a work of uncommon insight.

“It was very moving,” Shields says. “It’s unusual to hear writers say such wonderful things about each other.”

A feeling of urgency

Admirers have celebrated the very existence of “Unless,” the story of a writer whose daughter suddenly chooses to live on the street. Shields enjoyed a few months of relative good health last year and hurried to get the book done.

The author acknowledges that the writing process was “a bit different” for “Unless.” As her longtime editor, Christopher Potter, explains, Shields usually turned in complete manuscripts that required little revision.

“Carol didn’t know whether she was going to live to finish it, so she wanted to put it on a fast track. As soon as she had a few chapters, she sent them to me, and they were quite rough compared to what I was used to,” says Potter, who is based in the London offices of Shields’ publisher, Fourth Estate, an international HarperCollins imprint.

Shields and Potter at times worked with the efficiency of a crack songwriting team. The author felt well enough last year to fly to France, where she has a home in the country, and meet with Potter. After breakfast, they would sit at the kitchen table and work on the text.

“He had a lot of flagged questions and I remember at least twice going to this little living room, where I have a computer, and I would write the new pages right then,” she recalls.

“That was something extraordinary,” Potter says. “She would send me into the corner of a room with a newspaper and type up the revisions and say, ‘What about this? Will this do?”‘

So far, reviewers have found “Unless” worthy of Shields’ previous work. Library Journal called it a “delectable investigation into human folly,” and Booklist found it a “gut-gripping story of one woman’s difficult psychological journey.”

Author of more than a dozen books, Shield is best known for “The Stone Diaries,” winner in 1995 of the Pulitzer Prize, the National Book Critics Circle award and Canada’s Governor General’s Literary Award. More than 700,000 copies are in print.

“The Stone Diaries” follows the life of Daisy Goodwill Flett, “a middle-class woman, a woman of moderate intelligence and medium-sized ego and average good luck.”

From her birth on a kitchen floor in Canada to her retirement in Florida, Daisy lives through much of the 20th century, enduring childhood tragedy and a tragic first marriage, raising three children and emerging late in life as a popular garden columnist.

“I’ve been witness to this huge change for women in the second half of the 20th century,” Shields says. “They say you write the same novel over and over, and the idea of women being fully human has always been a preoccupation.”

Focusing on ordinary folks

Most American readers only learned about Shields after “The Stone Diaries,” but she has long been popular in Canada. Among her fans is the acclaimed fiction writer Alice Munro, who sent her an admiring letter after “Small Ceremonies” and later praised her as a “real writer.”

Shields has explored courtship, marriage, family and women’s roles in society. She is noted for writing about “ordinary” people, but has been unable to resist writing about artists from the murdered poet in “Swann” to the novelist in “Unless.”

“I always feel we shouldn’t be writing about writers, that other people aren’t necessarily interested in writers’ lives,” she says. “But I can’t resist. I know I’m sort of going against my principles by doing it.”

Shields not only writes about creative people, but uses creative ways to write about them. In “Swann,” her personal favorite, the final chapter is structured like a film script. “A Celibate Season,” a novel of letters exchanged between a separated married couple, was co-authored with Blanche Howard. In “The Stone Diaries,” Shields included photographs of her characters, gathering shots from museums, antique stores and a Parisian postcard market.

“I didn’t expect my publisher to let me do that,” she says with a laugh.

“Unless” is a straightforward, unillustrated story narrated by Reta Winters, a middle-age writer whose daughter’s breakdown leads to her own emotional crisis. “Happiness,” she observes, “is the lucky pane of glass you carry in your head.

“It takes all your cunning just to hang on to it, and once it’s smashed you have to move into a different sort of life.”

The novel was written quickly, but the title occurred to Shields 20 years ago. She was teaching at the University of Manitoba when a philosophy professor in the next office told her that his favorite lecture was called “Unless,” a concept meaning nothing is absolute.