Development Policy and Development Economics: An Introduction * Dani Rodrik and Mark R. Rosenzweig July 8, 2009 Anyone who undertakes to produce a volume of surveys in economic development must confront the question: does the world really need another one? There have been four volumes in the present series alone, going back to 1988 (Chenery and Srinivasan, eds.), with the latest collection published in 2008 (Schultz and Strauss, eds.). 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. But we had another motive as well. We envisaged this Handbook to have a somewhat different focus from earlier ones. In particular, rather than just surveying the “state of the literature” in various subfields, what we sought to accomplish is to present critical and analytical surveys of what we know (and don’t know) in different policy areas. We asked the authors of each chapter to answer the questions: “What kind of policy guidance does the literature offer in this particular area of development? Where are the gaps? What can we say with certainty that we know? What are the weaknesses of the literature from a policy perspective? What kind of research do we need to undertake to answer burning policy questions of the day? To what extent does actual policy practice correspond to the prescriptions that follow from solid research?” We thus envisioned that the audience for this volume would not only be graduate students and other * This is the introduction to Handbook of Development Economics , vol. 5 , Dani Rodrik and Mark R. Rosenzweig, eds., North-Holland, 2009, forthcoming.