The surplus of plutonium in the world is both an important security issue, and a fact with implications for nuclear energy and environmental policy internationally. The two perspectives are inextricably intertwined in considering options for dealing with the plutonium surplus. It was for this reason that two research programmes at the Royal Institute of International Affairs - respectively on Energy and Environment, and on International Security - jointly approached NATO with a view to organising a work shop on the issue. It was most welcome then to learn that the NATO Science Programe was already supporting plans for a workshop on the issue, initiated by Richard Garwin, and we were pleased to accept the resulting invitation to host that workshop. DrGarwin prepared the initial agenda and established contacts and initial approaches to many of the participants; we were able to develop the agenda further and extend participation in some complementary ways. The result was a most lively and broad-ranging internation al and inter-disciplinary discussion. As the hosts, the RIIA was also given lead responsibility for producing the pro ceedings of the workshop as a publication for NATO. Many of the papers to the work shop are more technical than usually involved in a workshop at the Royal Institute. Yet this is an area in which the policy options are unusually dependent upon a good under standing of the technical issues. which themselves are often a matter of dispute.