In Depth-David McCullough

David McCullough has twice received the Pulitzer Prize -- for "Truman" (1992) and "John Adams" (2001) -- and twice received the National Book Award -- for "The Path Between the Seas" (1977) and "Mornings on Horseback" (1982). His other acclaimed books include "The Greater Journey" (2011), "1776" (2005), "Brave Companions" (1991), "The Johnstown Flood" (1968), "The Great Bridge" (1972) and "The Wright Brothers" (2015). He is the recipient of numerous honors and awards, including the Presidential