Anyone who undertakes to produce a volume of surveys in economic development must confront the question: Does the world really need another one? The field changes over time and, one hopes, knowledge accumulates. So, one motive is the desire to cover the more recent advances. And indeed, economic development has been one of the most dynamic and innovative fields within economics in recent years. While one primary goal is to inform policy makers, it also hoped that the volume will assist scholars in designing research agendas that are informed by policy questions, in particular, by the gaps in knowledge that would speak to major policy issues. The development field has always been one in which the worlds of research and practice are in close relationship with each other and move in tandem. The large number of PhD economists who work in international organizations such as the World Bank and the influence of academia among developing-country officialdom ensure that ideas emanating from the ivory tower often find quick application. But equally important, in principle, is the reverse feedback—the need to tilt researchers' attention on the questions that are, or should be, on the policy agenda. The organization of the present volume around policy issues is designed to make a contribution toward both of these goals.