This report documents a preliminary effort to compile, analyze, and present data relevant to the feasibility of implementing a comprehensive preschool program within the St. Louis public school system. Sections of the study aim to provide (1) definition of and perspective on preschool education, (2) determination of the demographic "need" for preschools within St. Louis, (3) review of the preschool literature, (4) results of three separate field investigations, (5) analysis of different theoretical/curricular models of preschools, and (6) presentation of models appropriate to the school system, including examination of the relative merits, deficiencies, costs, and commonalities of two types of preschool: regular-day and extended-day programs. The section devoted to field investigations reports a survey of existing preschool programs in 20 St. Louis suburban school districts, offers insight into the efficacy of a presently operating preschool in reducing grade retention, and reports on observations and ratings of the environments of 15 local preschools. Appendices provide a summary of studies included in the "Persistence of Preschool Effects Report, 1977," a summary of observations performed and other data gathered from 15 St. Louis preschool centers. (RH)