Book excerpt: The degradation of land and water resources as a result of agricultural activity has had an enormous impact on human societies and economies. It is predicted that, by 2025, most developing countries will face physical or economic water scarcity, compounded by land degradation. In order to alleviate this problem, an advanced understanding of the state of our water resources and the relationships between land use, water management and social systems is needed. Conserving Land, Protecting Water includes an overview of global patterns of land and water degradation and discusses new insights drawn from successful case studies on reversing soil and water degradation and their impact on food and environmental security.