Dry areas suffer not only from limited rainfall but also 'natural leakage'--90% of rainwater is lost directly or indirectly, and is unavailable for agriculture or domestic use. Water harvesting is a low-cost, easy-to-use, environmentally-friendly way to recover a large part of this lost water. How does water harvesting work? Which sites or areas are best suited and how can these areas be identified? How to design, build and maintain a water harvesting system tailored to local needs? How can water harvesting contribute to combating land degradation, enhancing food security and adapting to climate change? This book provides the answers. The book is based on many years of research, training and development by three of the world's leading experts in water management and agriculture. It is authoritative, comprehensive, and easy to read, containing practical examples, many illustrations and little jargon. This volume will be of great interest to researchers, development workers, farmers, policymakers, students of the natural sciences--in fact, anyone interested in efficient, sustainable management of water resources and agriculture.