Nico Schrijver is part-time Professor of International Law at Leiden University and serves as State Councillor in the Council of State of the Netherlands.Niels Blokker is Professor of International Institutional Law at Leiden University and was previously Deputy Legal Adviser at the Ministry of Foreign Affairs of the Netherlands. Both of them have extensive work experience in the UN system, either as a member of expert bodies or as a delegate. Earlier they co-edited The Security Council and the Use of Force. Theory and Reality - A Need for Change? (Brill, 2005) and Immunities of International Organisations (Brill, 2015). In each of these publications they seek to bring together the perspectives of both academics and practitioners.