This study was concerned with the utility of the secularization concept for understanding processes of religious change. From initial consideration of the previous sociological treatment of the secularization concept, as found in church-sect literature, it was argued that a redefinition of the concept was necessary for two reasons. First, the usage of the secularization concept within church-sect literature lacked clarity of definition, and was too often associated with normative assumptions. Second, secularization in church-sect literature was often utilized to refer to both an ideological and organizational shift in religious organization, with no attempt made to distinguish between the two processes or test their association. For these two reasons, secularization was redefined in ideological and organizational terms, and operational definitions were developed conducive to sociological analysis. The remainder of this study considered the utility of the secularization reconceptualizations. The sacred-secular model of ideological secularization was applied to major shifts in Protestant theology in the 20th century in an effort to test it's utility for contrasting the nature of these shifts. Both the ideological and organizational secularization definitions were applied to a particular church setting in order to test their utility for isolating religious change. Lastly, this study recommended a number of possible alternatives for further sociological study of the secularization process, as understood in ideological and organizational terms. / M.S.