Abstract
The author presents a general background to the discussion of conversion to Islam in Europe by restating an outline of what is known about the social form of religion in contemporary Europe. This concept (social form of religion) identifies the most important social and cultural determinants of the institutional and/or non-institutional location of religion in the major historical types of the social organization of human life. The prevailing social form of religion in contemporary Europe is marked by privatization, marginalization of the traditional Christian form of religion, and structural cementing of increased options for individual bricolage. The main courses leading to the prevalence of this social form of religion are structural differentiation and a modern form of pluralism: the main consequences with respect to conversion are a changed frame both of subjective and social plausibility for the change from one optional way of life to another.