This work describes and analyses the operation of international institutions in the aversion, regulation and mitigation of non-international armed conflicts. The first part covers the basic legal principles governing civil wars, while the second part examines practice. Issues looked at include the status of parties to the conflict, the role of the UN and its agencies, peacekeeping, peacemaking, humanitarian relief, modes of resolution and settlement and liability for unlawful conduct. Post 1945 conflicts are examined, including Yugoslavia and Somalia.