Writing with authority and brio, Giulio Boc­caletti—honorary research associate at the Smith School of Enterprise and the Environment, Univer­sity of Oxford—shrewdly combines environmental and social history, beginning with the earliest civ­ilizations of sedentary farmers on the banks of the Nile, the Tigris, and the Euphrates Rivers. Even as he describes how these societies were made possible by sea-level changes from the last glacial melt, he incisively examines how this type of farming led to irrigation and multiple cropping, which, in turn, led to a population explosion and labor specialization. We see with clarity how irrigation’s structure informed social structure (inventions such as the calendar sprung from agricultural necessity); how in ancient Greece, the communal ownership of wells laid the groundwork for democracy; how the Greek and Roman experiences with water security resulted in systems of taxation; and how the modern world as we know it began with a legal framework for the development of water infrastructure. Extraordinary for its monumental scope and piercing insightfulness, Water: A Biography richly enlarges our understanding of our relationship to—and fundamental reliance on—the most elemental substance on earth.