* Includes never-before-published letters and photographs * Written by an Irvine family member Mallory and Irvine. These two names have been inextricably joined since the two climbers disappeared on Mount Everest more than 75 years ago. Could they have been the first to reach the summit of the world's highest mountains-some 30 years earlier than Edmund Hillary and Tenzing Norgay? Mallory's story has been well chronicled, but Irvine has always been...