If we could prompt our leaders to make good decisions, we could lessen global warming and avoid huge problems with oil spillage and nuclear waste. Of course we’ll still have problems on the planet, but we’d be better off.

You chose to shoot in black and white, on a Hasselblad camera, which is somewhat cumbersome when you’re traveling. Why?
I think that black and white alters time, making it seem to stand still. We see so many color images every day; a lot of them become ordinary. I’m proud of the fact that I’ve used the same Hasselblad camera for thirty years. When I first rented a Hasselblad for a shoot, in my early twenties, my heart took a leap. I loved the weight of it, the square format. It made me feel that it wasn’t so easy to just snap away. Every image had to be significant.

What are some of your favorite images in the book?
It’s hard to choose, because they’re all my babies in some way. But there are three that, for me, particularly express the story of tribes in transition. One is actually titled Tribal Man in Transition. It’s one of the first images I made on that early journey to Kenya. I was at a roadside market in the middle of nowhere, and this man came forward to ask for his portrait to be taken. The light was beautiful, and he was extraordinary: he’s wearing a ragged T-shirt but he has a timeless, iconic face and the essence of a hero. The other two are Aboriginal Artist and Hawaiian Chanter. I feel that the image of the artist expresses the weight and sorrow of a culture that’s been denigrated. The same with Chanter, who has a tear rolling down her face.