Review of anthropological studies on the Azandi tribe and nomadic tribal groups in southern Sudan, and collection of information through interviews and participant observation, provided the basis for a study of the functioning of and changes in tribal social organization and culture. The study is an attempt to investigate the way in which improved agricultural practices can be adapted to the traditional system of shifting cultivation, to raise the production of food crops as well as of newly introduced cash crops. In particular, it attempts to set forth certain concepts and methods which are needed to develop a general methodology for building up an effective agricultural extension service to meet the social and economic needs of the backward tribal societies in Sudan. Tribal social emergence and economic advance have three prerequisites: the proper social machinery and adequate social receiving apparatus; social mobility; and development of progressive tribal leadership. (author/mf)