This article offers a methodological framework for the study of the sociogenesis of the use of the category “Muslim” as the main figure of otherness in Western Europe, and proposes some lines for comparison among the cases in this monographic issue, that is, Spain, Norway, France and Britain. It places our analytical outlook within a selection of the comparative literature on Islam in Europe, presents our rationale for an event-based and multiscalar perspective on the development of national public debates, discusses the impact of journalists and academics on the public experience, and opens questions on the degree of rigidification of the category and the configuration of polarization around it in each context.