Abstract
The author attempts to calm fears which arise, among ecclesiastical authorities and faithful, from explanation and analysis in the field of the sociology of religion. In so far as the Church is at the same time a temporal and spiritual society the sociology of religious groups complements the field of theology. But springing from an empirical science, the results of sociological investigation, given the complexity of religious phenomina remain relative. Such investigation however usefully underliness the fact that the Church exists « in the world ».