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.

We searched around the globe and looked at well over a hundred 'Marco Polos,' came down to the wire, and went back and looked at our Italy tapes, and we realized that we had overlooked someone. That was Lorenzo Richelmy.

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.