Jerome Drevon's Institutionalizing Violence is a remarkable piece of scholarship. It advances our theoretical understanding of Salafi groups' radicalization and de-radicalization, and the centrality of institutionalization to groups' strategic choices. Its empirical chapters, focused on Egyptian Salafi-Jihadi groups, are fascinating, the result of exceptional access to important figures in these organizations. Drevon also has a unique ability to breathtakingly tell their story. This book is a must read for students of social movements, terrorism studies, and the Jihadi movement.