The thesis presents a case study of social change of a socio-economic area in the Northern Province of Sierra Leone, an area centred on the town of Lakeni (pop. 14,000 approx.) In the first section the conceptual framework and theoretical orientation is expounded and a two-level concept of social structure is defined and described. The relationship of the two levels, described in the thesis as being social structures of low and high stability, to other theories of structure, in particular those of F. Barth and F.G. Bailey is delineated. The second section is devoted to an analysis of the geographical background, the technical environment and the high stability structures found in the area. The high stability structures established are those of Village, Town and Administration and the section ends with an account of the few high stability links between them. The third section deals with low stability structures, in particular those that concern the relationship between the high stability structures. A fairly detailed analysis is made of entrepreneurial activities in which resources in one high stability structure are converted into capital in another. The analysis concentrates particularly on such activities which create a political profit for the actor. The section winds up by arguing that the socio-economic area appears to be acquiring at least some of the attributes of a region, defined sociologically. A short section IV concludes the thesis by describing some of the implications of the study to the selection of further areas of research and its implications to the theory of social change.