Peace is seldom concluded when a peace deal is signed. The principal external role in consolidating peace frequently falls to United Nations (UN) missions and agencies. Their ability to achieve this task is contingent on many factors including resources and cohesive international political support. It depends most critically on effective leadership. What are the unique, defining challenges to UN leadership in conflict and post conflict environments? How have effective UN leaders approached these challenges? The HD Centre is proud to have hosted Fabrizio Hochschild, during his UN sponsored sabbatical leave to write a critical study – the first of its kind – on this subject. He reviewed the relevant literature and interviewed dozens of leaders involved in mediation and peacemaking, including many associates of the HD Centre. This is the result of his work.