Interregional cooperation in peace and security as key feature of the EU external relations is particularly relevant in Africa-EU relations. However, these efforts have not been systematically evaluated to date. Focusing specifically on interregional peace operations, this volume provides the first comprehensive evaluation of the Africa-EU Partnership on Peace and Security. It explains the effectiveness of interregional security cooperation across three cases: (1) the AU-EU response in the Central African Republic (2013) and (2) in Somalia (2007–2017), (3) and the ECOWAS-EU efforts in Mali (2012). The book makes a valuable empirical, theoretical, and methodological contribution to EU foreign policy, comparative regionalism, and conflict studies.