More than a billion people live in extreme poverty, and many face the possibility of never escaping from it. Millions more may be at risk of falling into poverty. These risks are exacerbated by natural hazards, ill-health, and macroeconomic volatility. This massive, widespread vulnerability to poverty has become one of the defining challenges of our times. To effectively combat it, we need to better understand vulnerability, particularly in developing countries where people do not have the same bulwarks against risks as those in more developed nations. Through essays from leading scholars, this volume focuses on critical dimensions of vulnerability in developing countries, such as its relationship with poverty, and vulnerability arising from poor health and external shocks. Reflecting the multidimensionality of vulnerability, it showcases a variety of methodologies that offer new perspectives on the notion of vulnerability in economic development. Case studies range from some of the largest countries in the world, such as China and India, to countries in transition, small island states, and failing states. This book is a timely reminder of what remains to be done to reduce the risk of poverty.