Helping undergraduate college geography students understand the processes and forces which, in the name of modernization, continue to intensify a world spatial disequilibrium in the relations of people and resources is the purpose of this resource paper. It presents current ideas in social science research on modernization and development with particular reference to underdeveloped countries, especially the characteristics of underdevelopment and the geography of modernization. Part I deals with characteristics of underdevelopment and some frequently propounded views of the nature of underdevelopment and development. Part II examines causes and consequences of underdevelopment, especially external and internal causes and urban and national development in the postindependence era. Part III describes research about modernization in the underdeveloped world carried out by geographers. The paper ends with a review of findings and suggestions for kinds of research and research institutions that will aid, not hinder, Third World development. Many illustrative figures and tables and a comprehensive bibliography are included. (Author/ND)