Elixir spans five thousand years, from the beginnings of civilization to the parched American Sun Belt of today. It is a story of human endeavor: our present-day interaction with this most essential resource has deep roots in the remote past, and every human culture has been shaped by its relationship to water.For the earliest hunter-gatherers, knowing where to find water was a matter of life and death; the "songlines" of Australia's Aborigines define the whole landscape as a map of sacred water sources. In many agricultural societies, from Africa to the rice fields of Bali, a communal "water philosophy" surrounds the precious resource with social traditions that preserve fair access for people upstream and down.The sweeping narrative moves from the Greeks and Romans, whose mighty acqueducts still water modern cities, to China, where emperors marshaled armies of laborers in a centuries-long struggle, still ongoing today, to tame the country's powerful rivers.