In the 1980s and 1990s, green manure/cover crop (GMCC) systems became a popular agricultural technology in research and development efforts for smallholder tropical and subtropical farmers. However, few syntheses of these experiences have been conducted. This volume of case studies contributes to bridging this gap by reviewing field-level experiences with these systems. Twelve case studies are included. Eleven of them describe experiences from Latin America (4 cases), Africa (6 cases) and Asia (1 case) and the twelfth case reports on the development of a GMCC systems database. Two concluding chapters, `Learning from the Case Studies' and `Future Perspectives', build upon the cases. The systems described are diverse. Some systems have been spontaneously adopted by farmers, while others have been introduced to the farmers through diffusion efforts. Some of the cases reviewed describe small, localized efforts while others report on large-scale, well-known ones, such as the combination of GMCCs and conservation tillage in Santa Catarina, Brazil, the maize-Mucuna system in northern Honduras, and the improved fallow systems in Eastern Zambia. Most experiences include both development and research aspects and to the extent possible the cases integrate these two. Discussion of the strengths and shortcomings of the systems and efforts is frank, and the goal is to learn from these experiences to benefit future efforts. It is expected that both researchers and development practitioners and students of tropical farming systems and soil management will find this volume of case studies useful.