This book sets out to describe the reality of wastewater use in agriculture in developing countries. Its 11 thematic chapters explore a number of issues to understand the different dimensions of the problem, including a classification of the different types of wastewater use, the need to take a livelihood based approach focused on farmers, the need for public health guidelines, and an analysis of the cost-effectiveness of treatment required to meet the guidelines. The case studies from different countries demonstrate the wide range of wastewater use practise around the world. Finally, it summarises the lessons learned, makes recommendations, and points to future research needs that could contribute to safe and sustainable wastewater use in agriculture.