We live in an increasingly stressful world. There’s an aspirational sense things should improve with time, witness the U.S. War on Poverty or the U.N. Millennium Development Goals. But in the last 50 years, many risks, perceived and real, have grown worse: extreme weather, violent conflict, economic dislocation, poverty (especially for children), abuse and domestic violence. Traumatic and chronic stress affects millions. Many become sick and marginalized because of it; others manage to survive and thrive. What explains the difference?