DECLINING public school enrollments have in recent years been accompanied by the sustained growth of non-public schools. Indeed, since 1975 the latter have registered enrollment gains of 1 percent or more each year. But among these the fastest growing-and least understood-are the schools sponsored by fundamentalist Protestants. Christian schools, as they are typically called, have been described by one official of the now-defunct Office of Education as “the fastest growing segment in private education today.” At the same time, because these schools typically shun the inquiries of outside organizations, we have no hard evidence on how widespread they are. Nevertheless, data presented in a recent study sponsored by the National Institute of Education suggest that over the decade from 1965 to 1975 Christian school enrollments may have trebled. The same study goes on to estimate total national enrollments in fundamentalist-oriented schools at 900,000-or about one-fifth of all non-public school enrollments.