Sustainability and CLTS: Taking Stock || Durabilité et ATPC : État des lieux || Sustentabilidade e CLTS: Ponto da Situação

Each of three overlapping phases in the history of CLTS has presented its own major features, preoccupations and priorities: 1. Early growth and acceptance. Creativity, rapid learning, credibility. Refining methods, start-ups in countries, establishing bridgeheads, facing down scepticism, resistance and rejection, finding and supporting champions. 2. Going to scale. Rapid national, international and organisational spread. Maintaining quality in training and performance, verification, knowing the field realities. 3. Mature engagement. Sustainability and scope. Post-ODF (Open Defecation Free) follow-up, marketing and the sanitation ladder, problem nvironments, environmental risk when pits are emptied or replaced, diversity, depth and breadth of research to refine CLTS, wider frontiers. In recent years, sustainability of ODF conditions in rural areas has repeatedly been a top concern in workshops and conferences. Other issues of this series will explore and review wider frontiers and aspects of scope and diversity. This issue seeks to summarise and take stock of what we know about sustainability, practical implications of that knowledge, and what more we need to know.