I think of myself as a writer who photographs. Images, for me, can be considered poems, short stories or essays. And I've always thought the best place for my photographs was inside books of my own creation.

Life rarely presents fully finished photographs. An image evolves, often from a single strand of visual interest - a distant horizon, a moment of light, a held expression.

I was asked by a student what my most significant accomplishment was at National Geographic, after thirty years, and I said that my career came to an appropriate close, and I still loved photography. Not everybody who spends their career at anything ends up fascinated and involved with it.

My father taught me photography. It was his hobby, and we had a small darkroom in the fruit cellar of our basement. It was the kind of makeshift darkroom that was only dark at night.

There are a lot of ways to talk about the life of a photograph. You can talk about the afterlife of a photograph, and in the end I talk about that, with the Richard Prince picture. But mainly, what I dedicated the book to being about was how photographs begin their life, and where they begin it. And they begin it with the photographer's imagination and instinct and experience.

The class that I teach is called "The Life of a Photograph." It takes up the question, of the billion photographs that were taken today, how many will have a life, and why? So the new reality has made the question more pertinent, not less pertinent.

A mad, keen photographer needs to get out into the world and work and make mistakes.