Since 1945 the problems surrounding development or growth have aroused far more interest in the economic world than any other subject, perhaps than all other subjects put together. We need not explore the genesis of this enthusiasm, but it is evident that it has two quite separate roots: on the one hand the desire to raise the standard of the economically and socially backward countries, on the other the anxiety to secure that the economically forward countries go on going forward and do not slip back into the apparent stagnation of the 1930’s. The economic analysis springing from these two roots have certain aspects in common (especially the emphasis placed on the need to secure a higher rate of investment and saving); but the economic and institutional background in the two types of country are so different as really to constitute them different spheres of discussion. It is convenient to refer to the problems of the developed countries as concerned with growth, most of their resources being already known and largely developed, apart from certain minerals for which uses have only recently been discovered. The problems of the backward countries can then be regarded as those of development of hitherto unused sources whose uses in general are, however, well known. We are here concerned only with the study of development in this sense.