Our task here is to inquire into the relations between two familiar sets of phenomena—the economic development of the Western Hemisphere and the involvement of British investors, financiers, engineers, contractors, and financial groups in railways in that area. As a matter of convenience we shall look chiefly at the United States and Argentina, and at the time span of three quarters of a century preceding the First World War. It is no secret that during that period both countries underwent rapid development, whose contours included such matters as the effective occupation of new areas of vast extent; the growth of population, partly fed by immigration; the effective application of technological improvements to the exploitation of natural resources; an increasing complexity of the division of labor; and a rise in productivity and real income per capita, participated in by large segments of the population. During the same period, the Western Hemisphere was normally the outlet for from 40 to 60 per cent of British foreign investment, the United States and the Argentine being two of the countries chiefly affected. We are familiar with estimates that British investments in the United States, on the eve of the First World War, amounted to over 4 billion dollars, approximately 3 billion of which were in railway securities, and that something like half as much was invested in Argentina, with a somewhat smaller percentage directly in rails.