In an excerpt from a 1991 interview, Philippe Petit talks about his experience walking on a tightrope between the Twin Towers of the World Trade Center in 1974. Then, Colum McCann, whose novel "Let the Great World Spin" takes place on the day of Petit's adventure, talks with Steve Paulson. McCann was born in Dublin but lives now in New York. His father-in-law escaped from the first tower hit on 9/11. "Let the Great World Spin" just won the National Book Award for Fiction.