The case histories of water and sanitation schemes described in this volume can best be understood by identifying the moments at which critical hurdles were encountered and surmounted. The first case study, which concerns Bangladesh, discusses promising prospects that existed amid the pollution and the technical and managerial expansion of the crash phase of 1972-1976. Also discussed are moves towards community participation; the linking of water to sanitation and health; increased community outreach and changing technological challenge in the 1980s; and the broadened health impact. The second case study, which concerns India, describes program management in the 1970s; the process of advancing technology through handpump innovations; community involvement and maintenance; the move from technology transfer to capacity-building in hardware; the public health dimension of strengthened software; a push for water for all in 1985; and dracunculiasis eradication. The third case study, which concerns Nigeria, offers a blueprint for multisectorial and integrated action using low-cost technology. Topics include promotion of behavioral change through health education; the adoption of drilling and borehole technology; the move from pilot project to national strategy; evaluation of the impact on health; a redesigned software strategy; and the process of scaling up rural water projects. (RH)