This study focused on the development of policy thought, or abstract thinking about policy issues. Political thought may be described as concrete thinking about political phenomena. It includes one's knowledge of and attitude toward objects, people, and events in the political sphere. Policy thought entails the abstract manner in which one conceptualizes and approaches policy issues. Policy thought necessarily encompasses political thought. Political thought may be considered a necessary but insufficient basis for policy thought. The three purposes of this document are: (1) to provide a review of the research regarding the development of policy thought, including in-depth interviews with children and adolescents, the studies of specific aspects of formal operational thought, and the studies of the relationship between policy reasoning and other developmental theories; (2) to discuss the implications of the research for the development of children's policy thought; and (3) to offer suggestions for future research in the area of policy thought. The conclusions suggest that the development of policy thinking is related to age, that political interest seems to affect the level of policy reasoning, and that the development of policy thought appears to be related to other developmental models. A 57-item bibliography of references and three tables that compare various aspects of studies reviewed are included. (JB)