This book approaches the field of Political Islam from a European security perspective. Featuring various case studies and country surveys written by respected experts in the field, it offers a comparative perspective and comprehensive overview of the ideology and prevalence of Political Islam and its actors in more than 20 European states. The respective contributions identify key actors of Political Islam and reveal the activities, means, and strategies they pursue and employ across the continent. They also discuss if and how Political Islam could undermine the Western liberal democratic order and its associated values. By doing so, the volume offers approaches to analyzing Political Islam and thereby strengthening the resilience of liberal democratic societies, while also protecting Muslims from the radical ideology and agenda of Political Islam.