In the early 1980s, John Pakenham walked a total of 1,500 miles, with a series of companions from the local Turkana and Samburu tribes and their long-suffering donkeys, around a lake in the Great Rift Valley of northern Kenya. Repeatedly beset by extreme thirst and dehydration, bitterly cold torrential rains, poisonous spiders, vindictive mosquitoes and the ever-present threat of bandits, not to mention a fatal fight between two of his companions, he was lucky to live to tell his tale. Pakenham's account provides a rare glimpse of a tough terrain and its even tougher inhabitants, where every day was a battle for survival. This is extreme travel that, four decades on, still packs a powerful punch.