Then she won the part of Penny Lane, head "Band-Aide" in "Almost Famous," Cameron Crowe's rock 'n' roll crowd-pleaser. The part of a flighty, used groupie seems about as far from Polley, politically and in person, as possible. After weeks of rehearsal, she began to feel as if she'd made a huge mistake.

"The part didn't fit me. Every day, it felt less and less like something I could pull off," she recalled. "You just knew when you read the script that whoever played that part was going to have a certain kind of life, and it wasn't one I was ready for." She walked away, and Kate Hudson became Penny Lane, earning an Oscar nomination and a permanent place in the tabloids.

After the "Almost Famous" incident, Polley fell into a depression about her future.

She continued — and still does — to pop up as a player in a multitude of small Canadian films, most of which were never released outside Canada, but she questioned whether she wanted to be an actor. A viewing of the director Terrence Malick's "Thin Red Line" sparked an epiphany.

"It literally lifted and carried me out of this depression, and I had no idea movies could do that," she said. So Polley, at the age of 22, signed up for film school at the Canadian Film Center, where she directed two shorts.

Egoyan, an executive producer on "Away From Her," says he finds Polley's transition to director unsurprising. "There are two types of actors on a set: those who are very consumed with their performance, and those who are taking advantage of a front-row seat as to how a film is made," he said. "I always saw her spending a lot of time with the crew, watching the way the camera was moving, absorbing composition, movement. I could feel her eyes on me."

The film Polley has made is about emotional endurance, and it stars a cadre of enduring older performers who have managed to navigate the film world with their senses of self intact (she spoke enviously of the fact that Christie lives modestly in Britain and has a full life without acting).

In this way, "Away From Her" seems like Polley's effort to imagine some kind of future happiness for herself: as a married woman, and as a filmmaker in an industry she has known, if not loved, her entire life.

"For a long time, I felt extremely judgmental of the environment I was working in and the people I was working with," she said. "I don't feel like my politics have softened, but I don't feel like every single thing I do professionally defines me anymore. It's all experience. At this point, I'm open to anything. Even Hollywood doesn't scare me anymore."

Of course, Polley's version of the mainstream isn't exactly a summer franchise: She is preparing for a part in an HBO mini-series about John Adams, produced by Tom Hanks. "OK, so maybe it's not that commercial," she said, laughing again. "But for me, it's pretty slick."