This book recognizes groundwater flow as a fundamental geologic agent, and presents a wide-ranging and illustrated overview of its history, principles, scientific consequences and practical utilization. The author, one of the founding fathers of modern hydrogeology, highlights key interrelationships between seemingly disparate processes and systems by tracing them to a common root cause - gravity-driven groundwater flow. Numerous examples demonstrate practical applications in a diverse range of subjects, including land-use planning, environment protection, wetland ecology, agriculture, forestry, geotechnical engineering, nuclear-waste disposal, mineral and petroleum exploration, and geothermal heat flow. The book contains numerous user-friendly features for a multidisciplinary readership, including full explanations of the relevant mathematics, emphasis on the physical meaning of the equations, and an extensive glossary. It is a key reference for researchers, consultants and advanced students of hydrogeology and reservoir engineering.