When I was growing up I spent a lot of time reading about ancient China and was really fascinated.

I grew up with a fascination with Marco Polo. I had this unlikely interest in the East as a young man, and you can't really read about Chinese history and philosophy without encountering him at every turn.

I was interviewing an elder, Chief Fool's Crow, who was the ceremonial chief. He was 103 years old. I was getting his information on the history of Lakota horses. He told me the story of Hidalgo and Frank Hopkins.

In many ways, it's easier to write a book. You have more latitude with structure, and you have the freedom to luxuriate within the internal lives and musings of your characters. But where a screenplay does not always demand great prose, a novel lives or dies by it.