This article provides an overview of a number of changes that have taken place in the region's economy, together with their effects in terms of its social stratification, and analyses the different social sectors' options for political action. A series of economic changes have altered both the traditional heterogeneity of the Latin American economy and the relative weight of its various sectors; this is reflected, for example, 9n the heightened importance of agribusiness and the reciprocal penetration of the services and production sectors. Today a generic distinction between "incorporated" and "excluded" social groups is generally accepted, but these categories are not only imprecise and lack homogeneity; they also underestimate the relations that actually exist between the two, such as those frequently observed to have been established between the formal and informal sectors via subcontracting practices. As the heterogeneity of the regional economy changes, new sectors may come to exert an influence over social and political processes. This points up the need to review the conditions for collective action afforded by a capacity for organizing and broadening the base for a community of interests, whether as a means of corporate defence or as a way of presenting those interests as an agenda for society.