This resource paper on economic geography is part of a series designed to supplement undergraduate geography courses. It interprets regional economic development in terms of geographic spatial patterns of production, income, and physical or economic distance. Chapter two outlines some selected characteristics of spatial disparities of economic development at the regional and interurban levels in the United States and in developing countries. Chapter three briefly discusses two major theories of spatial development. The export-base theory explains the development of a region through external demand for its natural resources. The sector theory explains development through the specialization of agricultural activities and the formation of an intraregional transport system which permits the exchange of products. Chapter four reviews several models of differential mobility to explain in conceptual terms the emergence of the urban-regional structure in the United States. Chapter five analyzes selected flow of variables such as labor, capital, innovation, and decision-making power between developing and developed nations. Chapter six suggests five alternative national strategies of urban development. (Author/DE)