The definitive presence of a huge Muslim population in Europe will, of course, have long-term consequences.11xThis paper was first presented at the conference “Religion, Secularism, and the End of the West,” held by the Center on Religion and Democracy and the Institute for Advanced Studies in Culture in Laxenburg/ Vienna, Austria, on June 3, 2005. There is, nevertheless, some debate about the figures of the Muslim population, partly due to imprecise data, partly due to the difficulty of knowing who qualifies as a Muslim. Is one defined as a Muslim strictly because of one’s choice to belong to that religious community, or is one a Muslim by ethnic background? Beyond the demographic aspect, the fact that Islam is taking hold in Europe seems to put into question European identity. It is clear that the rejection of Turkey’s European Union candidature by European public opinion is largely linked to the fact that Turkey is a Muslim country. Furthermore, the assassination of the Dutch filmmaker Theo Van Gogh seems to have played a role in the Dutch rejection of the European Constitution in May 2005. What does the rise of Islam in Europe entail in terms of shared culture and values? Should we speak of “Islam in the West” as if Islam were the bridgehead of a different culture area, or of “Western Islam” as if a European Islam should necessarily differ from its Middle Eastern or Asian versions?