The distinction between "cultural" and "institutional" secularization is a necessity if the secularization debate is to be fruitful. Only by recognizing the different forces producing each of these kinds of secularization is it possible to understand the relative growth of the least secularized religious bodies in societies which, if anything, are still becoming more "secular." Wide variations in capacity to implement norms between denominations in the one society or culture are used to argue that histories of religious conflict, denominational schooling, etc., are at least as relevant for institutional cohesion as the forces of cultural secularization. If one studies the use of the much bandied about concept "secularization" in the literature dealing with church and society, it does not take long to discover that the various authors either use it primarily in the cultural sense "the forces whereby the influence of religion and religious institutions generally decreases in modem society" (cf. Acquaviva, 1964; Banning, 1951:84, 88; Glock and Stark, 1965:83; Heuvel, 1966:45-46; Leeuwen, 1964:331ff.; Lipset, 1959; Martin, 1965: 169ff.; O'Dea, 1966: 81; Salisbury, 1958: 197ff.; Tenbruck, 1960:122ff.; Vrijhof, 1964:107ff., 109; Wilson, 1966; Parsons, 1964:292); or in the institutional one"the forces whereby specific religious institutions and orientations themselves become both part of and like the world" (cf. Berger, 1967:3 ff.; Kraemer, 1964: 116 ff.; Pfautz, 1956:246, 1955:121 ff., 128). If they use it in both senses, they do so without discrimination. In the first instance, the research focus is generally on religion as the independent variable (it is taken as given, and the forces of social change are emphasized); in the second one, religion is the dependent one (it is adjusting to a secular environment which is taken as given). Both research foci are equally valid; but because the conceptual distinction is not made, it is too often assumed that there is a generalized process of "secularization" equally affecting religious bodies in the advanced nations as though it is a one-way street. We still know that it is sociological folly to jump too carelessly from cultural to institutional analysis and vice versa.' The need for the conceptual distinction arose particularly because in the author's own projects there was a range of phenomena (in the literature often used as the results of cultural secularization, such as apostasy, decreased church-going, not meeting religious norm demands) which could be much more satisfactorily explained by an investigation of specific religious institutions than of cultural processes. What are these phenomena, data, and