You find [reverberations from 9/11 ] in them most unexpected places, like graffiti on a wall. Sometimes it's a faded picture; sometimes it's a newspaper tacked to a wall. Sometimes it's weird paraphernalia related to it, home constructed paraphernalia. It resonates through society and continues to resonate today.

I was taking all prints and I brought them to the Magnum meetings, trying the old Josef Koudelka trick: Give them to photographers, who are getting bored during the talks about the economics of the agency, to look through with a pen. They'll separate them in two piles. I started to find the core pictures that people seem to relate to.

I began to explore America in more general terms. I really started this work in 2009. I got the bulk of it done as I was easing out of Disco Night.

You find [reverberations from 9/11 ] in them most unexpected places, like graffiti on a wall. Sometimes it's a faded picture; sometimes it's a newspaper tacked to a wall. Sometimes it's weird paraphernalia related to it, home constructed paraphernalia. It resonates through society and continues to resonate today.

Buzzing at the Sill is from a Theodore Roethke poem called "In a Dark Time." I'd heard a small part of it in a play, a sort of sci-fi play about morality in a virtual reality universe. Nothing to do with the book precisely, but it was a great play.

I went out to cover the wars in Iraq and Afghanistan fundamentally [in Buzzing at the Sill] because I was interested in war as a notion and in experiencing it. I was interested in history and how societies form. I was interested in the recent history of what had provoked these wars. So when I finally got out there, I was really seeing the wars through the American perspective, much more than through being embedded with American soldiers and Marines.

I am still covering conflict to some degree. I was back in Iraq. I've covered quite a bit of the Israel and Palestine. But I'm not doing it with the kind of intensity I was before and I'm not seeking out the front line and the kind danger that comes with being at the edge of the war the way I used to.