In 2004, an article in The Oregonian entitled "Out Of The Woods Police Rescue Father, Girl Who Say Forest Park Was Their Home For Four Years" piqued the interest of writer Peter Rock. A professor of creative writing at Portland's Reed College, Rock had earned a literary reputation for his skill in bringing to the forefront marginal characters who might easily go unnoticed. In his 1998 Carnival Wolves, for example, a recluse and his injured Dalmatian travel across America encountering pet tigers, taxidermists, and nearly feral human beings. His 2002 novel The Ambidextrist makes an outsider who earns money as a medical test subject its unlikely hero. As Rock-and most of Portland-followed with fascination the story of the mysterious father and daughter, the writer's mind filled with questions, characters, and ideas. Eventually he put them all together to create his 2009 award-winning novel My Abandonment , which was adapted by Debra Granik and Anne Rosellini as the basis for Leave No Trace. Perfectly precise in detailing its Pacific Northwest home, Rock's novel also reverberates with themes as old as Shakespeare's The Tempest. We spoke with the author about how he came to the story, why he couldn't shake it, and why it makes such a good novel.

Can you talk about the origins of My Abandonment?

In some ways, the novel grew out of another book I was writing called The Bewildered. That was about a group of teens in Portland who were hired to steal copper wire from high voltage lines. When I was writing that in 2004, there was an article in The Oregonian about a father and a daughter who had been found living in Forest Park and how they had been resettled. About a month or so later, there was a second story about how they had disappeared. As I waited for the next story, my mind, which is a fiction writer's mind, started thinking about them-imagining how they managed to live there for four years and wondering where they went.

How did you translate that fascination into a novel?

First, I put them in the novel I was writing. In The Bewildered, I incorporated this girl living with her father, since part of that novel takes place in Forest Park. But she was so interesting that she became a distraction. I did, however, keep parts of what I wrote about her in The Bewildered in My Abandonment, like her watching some of the earlier book's characters. I wrote the book, but I wasn't really sure I was going to give it to my agent. I wasn't sure if it was anything more than just a personal project. You see, my first daughter was born in 2007. My anxiety of being a father is all through that book. What do you tell them? How do you guide them?

Was the actual story still unfolding while you were writing the novel?

In a way. As I was writing this, I kept tabs on how people reacted to the Oregonian story. There were two main reactions people had, which I guess is very Portland-like. One was that this was a very hopeful story, and a sort of commentary on the commercial life we live. The father and daughter seemed to be thriving, happy, and devoted to each other and not distracted by all of the things that distract us. The second view was that they would be better off and happier if they lived like we lived-if they lived in a house and he had a job and she went to school.

Did you find this story about a father and daughter in the wilderness a kind of archetypal American story?

I think I felt it, but I am not sure I thought it. At the time, I was reading all the books the father might have read, mostly survivalist stuff like the works of Tom Brown, Jr. But I was also reading a fair amount of Thoreau and Emerson. There's a popular notion of Thoreau as a friendly, gentle recluse, but if you read him as someone with misanthropic tendencies, he comes off so cranky and paranoid. In the story, there is also that question of wilderness versus civilization, especially because that park is so close to the city. I was just there just the other day and it is so overgrown and so inaccessible in places that it is completely understandable how they lived there.

When you were researching the book, I understand you would hang out in the park to get a feel for what father and daughter did?

I would just ride over there and climb trees and hang out, taking notes about things I experienced. If I saw people, they might get incorporated in the book. If I saw a homeless person, I would pay close attention to how they were traveling and where they were going. In a way, I just made myself her. I tried to imagine what would be important to her-how she would move, what she would see, and what would the rules be that kept you hidden.

How do you think this book differs from your other work?

It's a different book because I've always been a little wary about writing about family. In my books there are a lot of strangers meeting each other, which is narratively productive because the reader is learning about characters as they learn about each other. Dealing with a child is a long-term relationship that I hadn't considered before. Recently I had my daughters' names tattooed on my arm (which is a longer story). I said to the tattoo guy I should be getting something for my wife as well. He told me, "I don't do wives or partners. That's just bad luck. But your relationship with your kids, no matter what happens, they are your kids." As true as that is, a relationship of a father and a daughter does change over time. That's part of the tension in both the book and film. She's of that age where she's no longer a child. She wants other things. For me the wilderness of parenthood is a wilderness of being responsible for another person over a long time.