Book excerpt: The conventional approach to river protection has focused on water quality and maintaining some "minimum" flow that was thought necessary to ensure the viability of a river. In recent years, however, scientific research has underscored the idea that the ecological health of a river system depends not on a minimum amount of water at any one time but on the naturally variable quantity and timing of flows throughout the year. In Rivers for Life, leading water experts Sandra Postel and Brian Richter explain why restoring and preserving more natural river flows are key to sustaining freshwater biodiversity and healthy river systems, and describe innovative policies, scientific approaches, and management reforms for achieving those goals. Sandra Postel and Brian Richter: explain the value of healthy rivers to human and ecosystem health; describe the ecological processes that support river ecosystems and how they have been disrupted by dams, diversions, and other alterations; consider the scientific basis for determining how much water a river needs; examine new management paradigms focused on restoring flow patterns and sustaining ecological health; assess the policy options available for managing rivers and other freshwater systems; explore building blocks for better river governance. Sandra Postel and Brian Richter offer case studies of river management from the United States (the San Pedro, Green, and Missouri), Australia (the Brisbane), and South Africa (the Sabie), along with numerous examples of new and innovative policy approaches that are being implemented in those and other countries. Rivers for Life presents a global perspective on the challenges of managing water for people and nature, with a concise yet comprehensive overview of the relevant science, policy, and management issues. It presents exciting and inspirational information for anyone concerned with water policy, planning and management, river conservation, freshwater biodiversity, or related topics.