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.

There isn't an aspect of book creation I don't enjoy, and there has always been a book in my life to dream about or work on.

There are grander and more sublime landscapes - to me. There are more compelling cultures. But what appeals to me about central Montana is that the combination of landscape and lifestyle is the most compelling I've seen on this earth. Small mountain ranges and open prairie, and different weather, different light, all within a 360-degree view.

I did a story for the Geographic on Meriwether Lewis and William Clark, and Stephen Ambrose was the writer. He said, "I've got the easiest job in the world. I just have to re-tell the story of the greatest fishing, camping, hunting, canoeing trip of all time. You, Sam, have the hardest job, which is, pretend like nothing has happened in the last 200 years.

Essentially what photography is is life lit up.

Above all, it's hard learning to live with vivid mental images of scenes I cared for and failed to photograph. It is the edgy existence within me of these unmade images that is the only assurance that the best photographs are yet to be made.

I have this awareness that the more dynamic the situation is, the more on guard I need to be that the dynamic isn't controlling the situation. I found that myself in the Galapagos. For the first time in my life I was around very exotic animals, colorful, beautiful, and immediately present, all around. Birds, turtles, iguanas, seals. I was being seduced by their exoticism, I was taking pictures.The pictures weren't well lit, there was no moment in play, there was no depth to the pictures. I was just gawking with my camera at something I'd never seen before.