David Grann, a staff writer at the New Yorker, was so obsessed about what happened to the great British explorer Percy Fawcett when he disappeared in the Amazon jungles in 1925 that he put his life on the line and followed Fawcett’s path to find out. “The Lost City of Z,” is Grann’s blockbuster adventure narrative about what lies beneath the impenetrable jungle canopy of the Amazon and what really did happen to Fawcett. If this and the fact that the book is a best seller aren’t enough to make you listen to my interview with David maybe the knowledge that Brad Pitt is making a movie of “The Lost City of Z” will.