Professor at the Department of Peace and Conflict Research, Uppsala University (1985-present,). Head of the Department of Peace and Conflict Research, Uppsala University (1972–99). Leader of the Uppsala Conflict Data Project. Coordinator of the Stockholm Process on targeted sanctions. Holder of Dag Hammarskjöld Chair.

Publications include: Understanding Conflict Resolution: War, Peace and the Global System (SAGE, 2002), Making Targeted Sanctions Effective. Guidelines for the Implementation of UN Policy Options (with C. Staibano and M. Eriksson, Uppsala 2003), Alva Myrdal in International Affairs (2003), Peacekeeping Operations: Global Patterns of Intervention and Success, 1948-2000 (2004. Research Report No 1, Folke Bernadotte Academy Publications, with Birger Heldt).