... here. I love this answer in particular:
Maria Schneider: You’re known as one of the great narrative nonfiction writers. What motivates you to write in this genre?
Susan Orlean: I love real life. I love finding and telling stories, with the deep hope that it will somehow change the reader. Fiction can do that too, of course, but I have always wanted to find real stories and draw people to them, reveal something of life to them that they might not otherwise have a chance to see.
The interview is on the blog, Editor Unleashed, well worth bookmarking if you haven't already.