WALTER CRONKITE IV is an associate producer with CBS News. MAURICE ISSERMAN is the Publius Virgilius Rogers Professor of History at Hamilton College. His most recent book is the prize-winning Fallen Giants: A History of Himalayan Mountaineering from the Age of Empire to the Age of Extremes, co-written with Stewart Weaver, which the New York Times called "the book of a lifetime...an awe-inspiring work of history and storytelling."