One of the more pervading characteristics of underdeveloped countries is the heterogeneity of conditions found in them. At whatever aspect of national life one cares to look, one is conscious more of differences than of a homogeneous national situation. Whether one looks at the people themselves, their environments, their cultures, their traditional economies, or social organizations, the compelling impression is one of diversity. This impression is stronger for countries with a large indigenous population, such as those in Africa and Asia, than it is for those in Latin America. The reason for the high degree of heterogeneity is partly historical – the fact that colonial powers in carving out spheres of trading influence for themselves, operated with scant regard to many of these factors. But the reason is also entailed in the fact of underdevelopment. Many of the communities that make up present national entities are still motivated by strong ‘primordial attachments’ of kinship, race, language, religion and custom. 1 In other words, many of these countries remain underdeveloped because they have not been able to integrate effectively a sufficient mass of population to achieve the type of change-generating interaction needed to move the social system to new and desirable heights.