Violence during war often involves upswings and downturns that have, to date, been insufficiently explained. Why does violence at a particular point in time increase in intensity and why do actors in war decrease the level of violence at other points? Duyvesteyn discusses the potential explanatory variables for escalation and de-escalation in conflicts involving states and non-state actors, such as terrorists and insurgents. Using theoretical arguments and examples from modern history, this book presents the most notable causal mechanisms or shifts in the shape of propositions that could explain the rise and decline of non-state actor violence after the start and before the termination of conflict. This study critically reflects on the conceptualisation of escalation as linear, rational and wilful, and instead presents an image of rebel escalation as accidental, messy and within a very limited range of control.

'Leading strategy expert Isabelle Duyvesteyn has created a new framework for our understanding of the mechanisms of insurgencies and COIN. Lucidly written, this book blends and builds on political science theories and behavioural psychology, illustrated with case-study vignettes, and rounded off with valuable advice for practitioners. An admirable achievement!'

Beatrice Heuser - Professor of International Relations, University of Glasgow

'This book is a most welcome innovative, nuanced, and probing analysis of the understudied dynamic processes of conflict escalation and de-escalation, with special insights about rebel violence. This work deserves special commendation for emphasizing that such processes can often be messy and inadvertent and for providing a robust conceptual and empirical challenge to commonly-held assumptions about their linear rationality.'

Bob Mandel - Professor of International Affairs, Lewis & Clark

'Isabelle Duvesteyn's book offers an original and highly stimulating new perspective on the notion of escalation and de-escalation in conflict. Her volume makes an important contribution to our knowledge and understanding of this under-studied and under-theorized area.'

M. L. R. Smith - Professor of Strategic Theory, King's College London