I think writers process their own experiences through the characters and situations they write. So for Batman, I used my own experience of losing a loved one. Grief is a strange place; it's like an altered state. You might sleep too much, so you can see the dead in your dreams.

I live in New York City, and one day many years ago I was with a poet, Gregory Corso, walking through Greenwich Village. He pointed to a doorway in an alley that he said led to a tunnel under Manhattan, a tunnel he'd use to run from the cops. I started learning about old Prohibition-era speakeasy tunnels under the city, for running whiskey.

Green Arrow has gone through so many changes; he's been right-wing, he's been left-wing, he's been rich, he's been poor, he's been a social justice guy, then when I got him, he was a rich playboy guy. So it was a lot harder to get into a character that has so many personas in the past, and I just looked at his anger.