IN THE SANDTOWN-WINCHESTER neighborhood of Baltimore, Maryland, during the 1980s, the statistics told a grim tale. Among a resident population of approximately ten thousand, half the families lived below the poverty line; 40 percent of the residents depended on welfare to survive; almost 30 percent of the new babies each year were born to single, teenage mothers; and the rate of AIDS infection was the fourth highest in the state. This could have been just another story of urban decay. But it isn't, because the people who live in this neighborhood decided to change things.

In 1990, they initiated a program called Community Building in Partnership, one of many programs involving poor people that are having an impact on poverty. That partnership involved funding from the Enterprise Institute, a nonprofit organization involved in revitalization projects throughout America. It also received funding...