This edited volume argues that the rise of Islamic conservatism poses challenges to Indonesia’s continued existence as a secular state, with far-reaching implications for the social, cultural and political fortunes of the country. It contributes a model of analysis in the field of Indonesian and Islamic studies on the logic of Islamic conservative activism in Indonesia. This volume presents informative case studies of discourses and expressions of Islamic conservatism expressed by leading mainstream and upcoming Indonesian Islamic groups and interpret them in a nuanced perspective. All volume contributors are Indonesian-based Islamic Studies scholars with in-depth expertise on the Islamic groups they have studied closely for years, if not decades. This book is an up-to-date study addressing contemporary Indonesian politics that should be read by Islamic Studies, Indonesian Studies, and more broadly Southeast Asian Studies specialists. It is also a useful reference for those studying Religion and Politics, and Comparative Politics.