For several decades, "culture" played a central role in challenging the liberal tradition and its legal and philosophical foundations, a debate particularly acute in the field of human rights. "Religion," which also had posed a challenge to liberal thought for centuries, seemed to have almost faded away beyond constitutional debates regarding the limits of free exercise. More recently, however, religion seems to have reemerged as the new central challenge facing Western liberal societies. This paper is the introduction to an edited volume that addresses the significance of the growing presence of "religion" in contemporary law and politics, and discusses the following questions: Has "religion" indeed taken the place of "culture" as a center of political tension and social integration? How have liberal democracies faced the rise of religion in the age of multiculturalism? Do religious and ethnic groups pose similar challenges to modern liberal societies, or are these challenges significantly different? Has the traditional struggle for "religious freedom" been transformed to a struggle for political recognition in line with the more contemporary "politics of identity"? Are contemporary discussions of a "post-secular" society similar to those of "multi-cultural" societies? Are notions of religious belief being merged with cultural practices to enlarge the constitutionally protected autonomy of minorities? Can this destabilize societies viewing themselves as multicultural by relying on a common foundation presented as secular? Can the notion of "citizenship" escape any religious overtone, given the significance of religious beliefs in the identities of so many groups constituting modern societies? Is "secularization" itself, as some have argued, "culturally biased"? Is "culture" in the final analysis nothing more than a "secularized" version of (Christian?) "religion"? More generally, what is the philosophical and legal sense of "religion" and "culture"? Have these concepts and the phenomena they represent undergone a historical change? Are we in need of new concepts, doctrines and theories to comprehend and resolve the new challenges of religious revival in the post-multicultural age?