This book explores the challenges of conflict resolution in protracted conflicts and conceptualises and analyses the practice of engagement without recognition in de facto states. Increasingly, engagement without recognition is seen as a promising approach to conflict resolution in de facto states, but little is known about its implementation and results. This book addresses that lacuna and develops an analytical model to assess international engagement, focusing on implementation on the ground. This model enables a comprehensive analysis of international engagement's scope, areas, and methods. Further, the book also explores the context of engagement in de facto states, which has a significant impact on its implementation and results. In this way, the book also advances our understanding of the opportunities, obstacles, and limitations of engagement without recognition. The analysis is based on the current EU engagement in Abkhazia and draws from other cases in the Caucasus, Eastern Europe, and beyond and finds that international engagement with de facto states is more comprehensive and multifaceted than previously known. However, it also faces some distinct challenges and produces modest results. Finally, the book provides practical recommendations on how to better utlilise the peacebuilding potential of engagement without recognition. This book will be of much interest to students of conflict resolution, statehood, peace and conflict studies, and international relations.