After an overview of the political history of Project Follow Through, this paper offers (1) an analytical history of the program, with special attention being given to the first years; (2) a description of model development and implementation; (3) an analysis of the role of longitudinal research in Follow Through; (4) a discussion of external issues in the next phases of Follow Through; and (5) a synthesis of Follow Through's history and its potential for the future. The analytical history describes changes in the program, activities of program sponsors, preselection of participating communities, program expansion after 1968, later developments, and the evaluation of the program. Model implementation is discussed in terms of the sponsor concept, the status of Follow Through sponsors in 1968, and documentation of sponsor performance. The section on longitudinal research presents arguments against using data obtained from third-graders as an ultimate test of program effectiveness, reviews followup studies of Follow Through programs, and concludes that further studies are needed. The exploration of external issues in the long term development of Follow Through provides a discussion of economic, demographic, and political trends. In conclusion, recommendations for ensuring the continuation of the program are offered: these include suggestions for followup studies and for the development of new program approaches. (RH)