This essay defines the concepts ofmodernization, development and progress, and identifies other concepts used in explaining social change at various levels of abstraction. Three theoretical perspectives are described, two of which, Smelser's value-added determinants of collective behavior and Myrdal's accumulative causation concept, are combined for use in analysis ofcase studies. These cases center around developing countries and regions, covering a variety of failure and success combinations with respect to directed change. The conclusions suggest that: 1) change will always occur; 2) accumulative or circular causation is a useful explanatory concept; and 3) systems have a structure such that elements of functional theories can be used to...