This book explores the process of assessing success in the field of conflict resolution, with a focus on the Action Evaluation method pioneered by the author. Since the early days of the field of conflict resolution, researchers and practitioners have been trying to determine how to define and assess success. Are its various approaches to engaging conflict effective? How is effective defined and operationalized and by whom? How might we know? Action Evaluation (AE), a methodology for defining, promoting and assessing success in and of the field, has been developed over the past two decades to answer these questions theoretically and in-use. It was designed from its inception to help create sound and contextualized standards around which the field could coalesce. AE is an appropriate methodology for evaluation of conflict engagement, in part because it is grounded in key values of the field, like participation, ownership and the constructive engagement of conflict among stakeholders in project development and implementation. By illustrating how AE is applied through case studies, and providing tools for others to use, this book is intended to make AE a more widely available, user-friendly and rigorous action-research tool for researchers and practitioners in the still-emerging field and beyond. This book will be of much interest to students of conflict resolution, peace studies, research methods and international relations in general, as well as practitioners in the field.