In the parched and seemingly lifeless heart of the Sahara desert, earthworms find enough moisture to survive. Four major mountain ranges interrupt the flow of dunes and gravel plains and at certain times waterfalls cascade from their peaks. Even the sand amazes: Massive dunes can appear almost overnight, and be gone just as quickly. We think we know the Sahara, the largest and most austere desert on Earth--yet it is full of surprises, as Marq de Villiers and Sheila Hirtle reveal in this brilliant and evocative biography of the land and its people.