This chapter describes what are judged to have been the most important changes in development economics, and evaluates their relevance to the circumstances of the economies of Africa. The important change in development economics to be noted here is the renaissance in the application of neo-classical analysis to development problems that occurred with the breakdown of the former concensus. The "neo-classical" is used loosely to refer to analyses that stress the efficacy of product and factor markets in the allocation of resources. Dependency theory seems to be of particular relevance to Africa, even though it has largely been developed for application to Latin America. The dependency theory of underdevelopment is still evolving, and may have more that is positive to offer in the future. The theorists, on the other hand, have contributed little of this kind because they see piecemeal reform as futile, and revolution as a necessary pre-condition of economic independence.