In this book I have attempted to give an account of the ecological and economic factors which affected the changing pattern of socio-political relations of two interlocking structures, the lineage and the polity, that accompanied the inauguration of the Jebel Awliya Dam Development Scheme in 1937. I have found it essential to give priority to ecological and economic factors as determinants of individual loyalties and interests, 1 rather than to the normative or ideological representations which are cast in the idiom of common genealogies and agnatic kinship. Within this framework, I have analysed the forces that have led to the increasing centralization of the former loosely structured polity of confederated lineages which arose from an emergent cohesive leadership and weakened lineages. 2