Sociology provides analytic perspectives for understanding specific ecclesiastic religious phenomena: that is, churches and church-oriented religions. The first definition, dating back to Weber is that of church as a specific kind of religious organization which enforces its decisions by means of psychic coercion, granting, and withholding religious benefits (“hierocratic coercion”), in a regime of territorial monopoly. Over time, the sociological idea of church as a specific kind of religious organization has encountered problems and limits. The ecclesiological question appears characterized by both the need to – and the difficulty of – accounting for very high degrees of complexity and for the equally high degrees and multiple forms of differentiation. Finally, this question shows the double requirement of not ignoring the organizational dimension and not reducing church to this. This last point is assuming a more and more crucial importance. On the one hand, the changing climate of the church–state relationship and returning to a sort of moderate secularism asks that more attention should be paid to the renegotiations of the structural coupling of religion and politics. On the other hand, the new secularization trend implies ecclesiastical religious organizations have to face more dramatic challenges than other kinds of religious organizations.