A project that obtained secondary data images on all nonpublic schools, secular and sectarian, in the United States is described. Original data were gathered for five in-depth case studies. This project was limited to an analysis of nonpublic schools through grade 12; it included several subdivisions. Studies on nonpublic schools were conducted in the following areas: (1) attitudinal demand, (2) present enrollment and projection of future enrollment, (3) costs and revenues with concomitant projections, (4) estimates of marginal costs to public schools resulting from nonpublic school failure, (5) in-depth analyses of costs, revenues, and marginal transfer costs in five selected cities, (6) a secondary analysis case study of determinants of enrollments in Catholic schools, and (7) an examination of criteria for aid to nonpublic schools with implications for public policy. It was found that: (1) American Catholics want their children to receive some formal religious instruction; (2) Nearly all Catholics are cognizant of the distinctiveness of both parochial and public schools; and (3) Quality assessments of educational programs, and subsequent decisions as to where to enroll one's children appear to be a function of one's personal set of education-related priorities. (For related document, see ED 058 473.) (Author/CK)