This book examines recent developments in the Horn of Africa region, the most significant in recent years being the July 2018 rapprochement between Eritrea and Ethiopia. Developments in Ethiopia, however, dashed the much-celebrated rapprochement; reform in Ethiopia encountered serious challenges, culminating in the war in Tigray. This book has three central themes: (1) the Eritrea-Ethiopia rapprochement; (2) the challenges of transition in Ethiopia; (3) peace, security and development in the Horn of Africa. The book aims to address such critical questions as: what factors led to the resolution of a festering conflict between Eritrea and Ethiopia? What is the significance of the Eritrea-Ethiopia rapprochement for peace and security? What are the challenges to the reform and transition process in Ethiopia?