Explorers once hogged the world's headlines and captured the public imagination to a degree that would be almost unthinkable today. Emerging from the jungle, desert or ice-cap, they were hailed as if back from the dead. Journalists fought for their favours and publishers rushed their narratives to a voracious public. Here is a selection of original first-hand narratives by famous pioneers such as Burton and Speke, Livingstone and Stanley, Mackenzie and Lewis, Peary and Amundsen...