Here is a story that rivals the search for the sources of the Nile and the race for the South Pole. As a challenge for explorers the mountain wilderness between India and Inner Asia was unique. The Western Himalayas were seen as a barrier guarding fabled cities unvisited since Marco Polo, barring the way for the commercial opening of Central Asia and Inland China. It took half a century to penetrate this barrier, evidence enough of the appalling difficulties involved.