Dr. Gary Slutkin spent a decade fighting tuberculosis, cholera and AIDS epidemics in Africa. When he returned to the US, he thought he'd escape brutal epidemic deaths. But he began to look more carefully at gun violence -- whose spread follows the same pattern as an infectious disease. His conclusion: We've reversed the impact of so many diseases, says Slutkin, and we can do the same with violence. A mind-flipping look at a problem that too many communities have accepted as a given.