The Organization of Firms in a Global Economy presents a new research program that is transforming the study of international trade. Driven by the availability of new micro data sets and innovative theoretical models, it focuses on the level of firms, products, and stages of production rather than on countries and industries. It addresses such questions as why only a small proportion of firms in a given industry export and why an even smaller proportion invest abroad; why exporters tend to be more productive than nonexporters; why almost one-third of international trade takes place...