Since 9/11 many books have been published on Islamic terrorism, but few of these have considered the issue from the perspective of strategic studies or in terms of an insurgency. As a result, much of this literature ignores the process of radicalisation and fails to ascertain why some people turn to terrorism, while others from the same background do not. To counter this trend, Explaining Islamist Insurgencies explains how and why the process of Islamist radicalisation is an important step towards acts of terrorism and in the formation of terrorist organisations by focusing on Poso, a small town in Indonesia that experienced years of armed sectarian conflict between Muslim and Chrisitian communities in 2000-2007. Building on the frameworks provided by previous studies, Muhammed Tito Karnavian employs communications theory to explore the necessary precursors for the legitimising ideology, in this case Salafi-jihadism, to be effectively disseminated.With nearly 20 years of experience in academia and counter-terrorism operations in Indonesia, and as the current Chief of Papua Police, Karnavian employs his unparalleled access to information and individuals to delineate the various stages of the radicalisation of the Poso conflict and how radical organisations, such as al-Jamaah al-Islamiyyah (JI), came to be involved. This unique first-hand account of a counter-terrorist operation concludes by offering general policy implications that will be of use to both academics and practitioners.