This book is based on a public-health approach to the provision of water and sanitation in emergencies: an approach that is information-based and people-based. It emphasizes the need for a coordinated and phased response, which adapts to meet constantly changing needs. Two kinds of reader will find it useful: non-technical managers of disaster-relief programmes, who need to understand how water supply and sanitation works; and technicians and engineers, who need to see their work in a broader context and make decisions based on principles of equity and participation. Topics include site-selection, disposal of excreta and solid waste, drainage, and hygiene promotion. The text draws on Oxfam's years of practical experience in this field, and on the recommendations of the Sphere Project on Minimum Standards in Humanitarian Response.