In 1915, while the Great War embroiled Europe, the world waited for news of the Antarctic explorer Ernest Shackleton's latest expedition but had given him up for lost. Shackleton's near-miraculous survival for nine months on the ice-packed Antarctic seas -- capped with an open-boat journey across more than 700 miles of the most dangerous weather in the South Atlantic -- has made him synonymous with courage and endurance. Roland Huntford, acclaimed...