The purpose of this book is to identify the optimal characteristics of a terrorist deradicalization campaign. A deradicalization campaign consists of all efforts a state or organization leverages to prevent the rise of or to disrupt terrorist organizations. A persistent difficulty with evaluating deradicalization "programs" stems from conflating different levels of analysis ranging from individual in-jail programs to broader national campaigns. The primary scope of this research extends to identifying key programs or factors required for state-run deradicalization campaigns to be effective. The initial framework used to evaluate these campaigns is composed of four lines of effort (LOE): individual disengagement, collective disengagement, individual deradicalization, and collective deradicalization. A series of mechanisms operationalize each LOE. This framework will be applied to historical and ongoing deradicalization efforts in Algeria, Saudi Arabia, Yemen, and Indonesia in order to develop relevant, empirically-based conclusions.