Reorganization is one of the most common activities of government, but it is not adequately understood, either by practitioners or by scholars. This article applies three broad approaches in administrative theory—purpo sive action, environmental determinism, and institutionalism—to the study of reform in industrialized democracies. Each of these three broad approaches is further divided into a number of more specific approaches. The article evaluates all the available approaches, and ends by arguing in favor of the institutional approach.