I am, professionally, an observer of animals — by which I mean nonhuman animals. I actually have been less interested in looking at people… But of course, as it turns out, the human animal is also infinitely more complex than I give us credit for. And I appreciated — a lot — the fact that, at the end of this book, I could take a walk with anybody — it didn’t have to be an expert… — and I became more appreciative of anyone’s perspective. If you can 
just get somebody to talk about what they see when they’re walking down the street, they will almost inevitably be seeing something different than you. Because they are a different person, and there’s a whole background there. And, actually, I think that is a kind of writerly trick — it’s sitting in the restaurant and making up stories about the people who sit around you… being interested in [them] and being able to imagine, backwards, their stories.