On 8th June 1924 Geroge Mallory and Andrew Irvine set off from camp at 26, 700 fett, bound for the summit of Everest. They were watched by Noel Odell who, in a famous despatch to ''The Times,'' described how the clouds parted to unveil the summit ridge and final peak of the roof of the world. He watched as the two black dots made towards the top, but after five minutes the clouds rolled in. They were never seen alive again. Did Mallory and Irvine conquer Everest almost 30 years before Hillary and Tenzing? How did they die? Where yhey the Olympian heroes described by history? And was George Mallory - friend of Lytton Strachey, partner the inexperienced young Irvine? 'An authoratitive book...prepared to debunk one of mountaineerings most cherished beliefs' - ''The Obsever.''