Peter Wallensteen is Professor Emeritus at Uppsala University and the University of Notre Dame, USA. He was the first Head of the Department of Peace and Conflict Research, 1972-1999. During that time Wallensteen initiated and led the Uppsala Conflict Data Program (UCDP), 1978-2015. He was the first holder of the Dag Hammarskjöld Chair at Uppsala University, 1985-2012. Since 2021 he is Deputy Chair of the Alva Myrdal Center for Nuclear Disarmament, Uppsala University and leads its working group on international measures for nonproliferation. His research includes economic sanctions, causes of war, mediation, conflict resolution and quality peace. Wallensteen has personal experiences as a third party in armed conflicts around the world. The volume Peter Wallensteen: A Pioneer in Making Peace Researchable (Springer 2021) explains his involvement in peace research, and presents ten fields he has contributed to. His Understanding Conflict Resolution is now in its 6 th edition (Sage, 2023, with editions in Arabic and Korean). Wallensteen has published on Alva Myrdal’s contributions to nuclear arms control (with Armend Bekaj, Springer 2022) and recently published The Peacemaking Mandate (on Nordic mediators, with Isak Svensson, CUP 2025) as well as Sanctions for Nuclear Disarmament and Non-Proliferation (with Armend Bekaj, Routledge 2024).