This collection of papers—which grew out of an effort initiated by the In- ternational Food Policy Research Institute, with preliminary contributions presented at three symposia between 1996 and 2001—intellectually flows from the strand of applied economics that has endeavored to measure the returns to investments in technology and scientific research and development (R & D). Having found handsome returns for many R & D ventures, especially in agriculture, this body of research has lent itself well to advocating continued and increased public support for science—to the delight of many a scientist but, in an age of increasingly tight budget constraints, with troublesome implications for those calling for equally strong support for social sciences. It seemed then to be a legitimate extension, hopefully leading to a bit of useful self-promotion, to ask a similar question of social sciences in general and economics in particular (and policy research specifically). The result is a wide- ranging assortment of contributions, sprinkled with methodological reflections and observations, and some data. The book contains 13 chapters, including some previously published papers but also several contributed or commissioned original pieces. At its best junctures the book is thought provoking, providing insightful remarks as well as useful analogies and valuable personal viewpoints. It thus succeeds in arousing the reader’s interest in a set of questions that do not usually command the attention of economists’ working hours. The relative novelty of some of the issues addressed may encourage further related work, which would make this book a useful starting point. Inevitably, however, some critical questions are left unanswered, while others turn out to be intractable.