This book explores state–religion relations under a populist authoritarian ruling party in Turkey. In doing so, it investigates how the ruling Justice and Development Party (AKP) instrumentalizes state-controlled religion to further, defend, legitimatize and propagate its authoritarian populist political agenda in a constitutionally secular nation-state. To exemplify this, the authors examine the Friday sermons delivered weekly in every mosque in Turkey by the Turkish State's Directorate of Religious Affairs (Diyanet). By analyzing all sermons delivered between 2010-2021, the book shows how the Diyanet has enthusiastically adopted AKP's increasingly Islamist, authoritarian, civilisationist, militarist and pro-violence populism since 2010, and how it has tried to socially engineer beliefs in line with this ideology.