Until now, there has been no direct and extensive engagement with the category of religion from liberal political philosophy. Over the last thirty years or so, liberals have tended to analyze religion under proximate categories such as 'conceptions of the good' (in debates about neutrality) or 'culture' (in debates about multiculturalism). US constitutional lawyers and French political theorists both tackled the category of religion head-on (under First Amendment jurisprudence and the political tradition of laicite, respectively) but neither of these specialized national discourses found their way into mainstream liberal political philosophy. This is somewhat paradoxical because key liberal notions (state sovereignty, toleration, individual freedom, the rights of conscience, public reason) were elaborated as a response to 17th Century European Wars of Religion, and the fundamental structure of liberalism is rooted in the western experience of politico-religious conflict. So a reappraisal of this tradition - and of its validity in the light of contemporary challenges - is well overdue. This book offers the first extensive engagement with religion from liberal political philosophers. The volume analyzes, from within the liberal philosophical tradition itself, the key notions of conscience, public reason, non-establishment, and neutrality. Insofar as the contemporary religious revival is seen as posing a challenge to liberalism, it seems more crucial than ever to explore the specific resources that the liberal tradition has to answer it.