It is no harder than it ever was to count and weigh goods as they cross frontiers. But technological change, the increasing internationalization of national economies and the growing importance of activities that are hard to measure, such as services and financial transactions, limit the value of the old figures. Moreover out-of-date statistical methods, limited funds, the lack of international comparability and a variety of other defects noted in this revealing book often make familiar data poor guides to policy. The panel of the National Research Council that produced this book (which included some excellent economists) takes a broad view of the problems. It emphasizes the need for figures based on the national ownership of companies and not just their location. How long will it be before another panel will have to analyze the difficulties of assigning a nationality to a thoroughly internationalized business?