This book empirically substantiates a re-conceptualization of Islam as produced and consumed by both Muslims and non-Muslims. Non-Muslim Islam is too often condemned and decried by scholars, rather than investigated. However, non-Muslim politicians, journalists, and public debaters preaching and missionizing their own interpretations of Islam to both Muslim and non-Muslim audiences, and venturing into theological debates with Muslims as non-Muslim Islamic authorities, cannot be reduced to cynical power politics, bigotry, political opportunism, prejudice, or apologetics (even if this may sometimes be the case). Neither do these labels increase our understanding of non-Muslim Islam as a phenomenon. This book argues the case for studying non-Muslim Islam and demonstrates the value of doing so through 11 case studies, opening up a new field of research, while also giving an insight into the many epistemologies at play in the production of different non-Muslim Islams.