This chapter explores the utility of articulation concepts in anthropological research on regional systems, with resulting theoretical as well as ethnographic implications. The articulation of modes of production approach argues that underdevelopment in the "Third World"—in all its variability and unevenness—should be understood as the effect of the articulation of a capitalist (though it could be state socialist or other) mode of production with one or several non-capitalist (or other) modes of production. In southwestern Peru most encomenderos established themselves in the pleasant temperate basin of Arequipa. Their wealth came not so much from their nearby small campina estates, however, as from the sale of sugar and its derivatives and wine and other products from large estates in well-watered valleys of lower ecological zones. Ongoing semi-subsistence production limits expansion of the home market, and therefore the possibilities for extension of capitalist relations.