The purpose of this paper is, generally, to discuss issues related to the evaluation of implementation and, specifically, to provide practical advice about Follow Through implementation and its evaluation. First, the discussion explores philosophical and theoretical assumptions regarding (1) the nature of implementation and evaluation; (2) realities of implementation as a unique form of socialization; and (3) approaches to evaluation that are compatible with the specified realities of implementation. Non-mechanistic, non-reductionistic philosophical assumptions and consonant theoretical positions are favored. Next, a discussion of realities of implementation provides a perspective on Follow Through evaluation efforts, analyzes implementation as socialization, and offers recommendations concerning the future of Follow Through. The concluding discussion of evaluation offers a concrete proposal for the evaluation of implementation. While many compatible evaluation stategies are listed, the judicial evaluation model is seen as the single approach most compatible with implementation realities, and a combined documenting and judicial evaluation approach is recommended. Briefly addressed are the inferential dimension of educational measures and the importance of Follow Through model sponsors. Appended is a rationale for a national Follow Through database that specifies needed categories of information and evaluation/research strategies. Also appended is a list of elements of child data and site descriptor computer files to be maintained at each Follow Through location. (RH)