Diarrhea caused by contaminated water is the single greatest killer of children in much of the world. In the 1980s, the Bangladesh-based organization to which I belong, BRAC, ran a program that helped reduce children's deaths from diarrhea by 80 percent nationwide. The project was fraught with difficulties and challenges, taking a decade to complete. Looking back years later, I think the experience holds important lessons that apply far beyond public health.
