This text is an introduction to ACRPS published The Islamic State of Iraq and the Levant (Daesh). It deals with a range of methodological questions to help understand the appearance of Islamic State (Daesh) as a phenomenon. It argues that as a complex, political, social and religious phenomenon, Daesh requires an approach that takes multifaceted and pluralistic perspectives. Hence, an integrated methodological approach, in which disciplines simultaneously overlap and reflect, examines Daesh within its context without neglecting its intellectual and religious characteristics. This paper argues that the existence of Daesh relies solely on war and expansion; once expansion ceases, extinction begins. It is a system that is built around a hostile environment, only remaining viable through a continuous state of expansion and regression. This introduction argues that the existence of Daesh relies solely on war and expansion; once expansion ceases, extinction begins. It is a system that is built around a hostile environment, only viable through a continuous state of expansion and regression.