Though Geographic didn't publish that photo in the story that it was done for, "The Life of Charlie Russell," a cowboy artist in Montana. But later, maybe a year and a half ago, they named it one of the 50 greatest pictures ever made at National Geographic.

That statement [ Stephen Ambrose:'You, Sam, have the hardest job, which is, pretend like nothing has happened in the last 200 years.'] woke me up to the fact that the landscape that Lewis and Clark came across was greater than the Serengeti. And it's gone.

When I first went to 'National Geographic,' I thought I was the least qualified person to step through the doors. But because of my parents and the culture of continual learning they imposed on us, I later came to believe I was the most qualified person who ever worked there.

In my first class at the University of Kentucky, my American Literature professor came in, and the first sentence out of his mouth was "The central theme of American Literature is an attempt to reconcile what we've done to the New World." wrote that down in my notebook, and thought, "What is he talking about?" But that's what I think about now. The New World and what we've done to it.

I wanted life to be episodic. I wanted to be a magazine photographer and I was willing to do what it took to become that.

My dad had been an ardent amateur photographer, and he taught me to compose a photograph from the back to the front, and then populate the picture.

It's more difficult now, to be a Geographic photographer, than it was when I came along. And it wasn't easy at that time.