"On May 13, 1945, a would-be pleasure tour for twenty-four U.S. Army servicemen and WACs turned into an unforgettable battle for survival when their plane crashed in the mysterious New Guinean valley known as "Shangri-La". Only three emerged from the wreckage. Emotionally devastated and badly injured, they faced certain death unless they braved a harrowing hike down the mountainside- a journey into the unknown that would lead them to a primitive tribe...

Diamond reveals how tribal societies offer an extraordinary window into how our ancestors lived for millions of years -- until virtually yesterday, in evolutionary terms -- and provide unique, often overlooked insights into human nature.