The subterranean sector-alternatively referred to as the informal, hidden, underground, shadow, secondary, black, invisible, or parallel economy--now constitutes an important component in the economic activities and process of development in the Third World. Although some Third World governments have tried in the past to minimize its relative importance, the subterranean sector continues to thrive in the Third World, where, generally, foreign-exchange constraints and inefficiency interfere with the normal functioning of the organized or formal sector, and therefore disrupts the availability and flow of goods, services, technology, and human resources in and out of those countries. The subterranean sector originally emerged in response to the problems of survival associated with rapid urbanization and unemployment in the Third World. However, this chapter will make it clear that it is not now a set of survival activities performed by destitute people on the margins of society.