It is as vast as the United States and so arid that most bacteria cannot survive there. Its loneliness is so extreme it is said that migratory birds will land beside travelers, just for the company. William Langewiesche came to the Sahara to see it as its inhabitants do, riding its public transport, braving its natural and human dangers, depending on its sparse sustenance and suspect hospitality. From his journey, which took him across the desert’s hyperarid core from Algiers to Dakar, he has crafted a contemporary classic of travel writing.