Henry Worsley’s lifetime fascination with Antarctic explorers comparable to Ernest Shackleton, Roald Amundsen and Robert Scott led him to retrace their expeditions in one of the inhospitable locations on Earth. In 2015 Worsley set off but once more to emulate his hero, Shackleton, by embarking on the primary solo crossing of the continent. Anthony Mason talks with David Gran, creator of the brand new e-book “The White Darkness,” and with Worsley’s spouse, Joanna, about her husband’s fateful journey.