This chapter provides new and important insights on the history of international business. International business activity grew vigorously in the 1920s, slowed down in the depressed and war-torn 1930s and 1940s, and then staged a heroic recovery in the 1950s, when it began a period of rapid growth which (albeit with fluctuations) has been sustained to the present day. While it has proved possible to make considerable progress in describing the multinational growth of firms and industries, the precise quantification of that growth has remained more elusive. Two broad approaches have been taken. The first approach has been concerned to construct historical estimates of the size and structure of foreign direct investment (FDI). The second approach has concentrated on counting multinationals. In Mira Wilkins’ various tables on FDI stock levels, Britain is shown as the largest host economy in western Europe at all her benchmark dates.