Two years ago, Harvard professor Kathryn Edin was in Baltimore interviewing public housing residents about how they got by. As a sociologist who had spent a quarter century studying poverty, she was no stranger to the trappings of life on the edge: families doubling or tripling up in apartments, relying on handouts from friends and relatives, selling blood plasma for cash. But as her fieldwork progressed, Edin began to notice a disturbing pattern. "Nobody was working and nobody was getting welfare," she says. Her research subjects were always pretty strapped, but "this was different. These people had nothing coming in."