The International Institute for Applied Systems Analysis (IIASA) has had risk as a research topic on its agenda right from its inception in 1972. Risk has played a - jor role in the Energy Program, with research being carried out both in-house and in cooperationwith other internationalinstitutions like the InternationalAtomic - ergy Agency (IAEA) and national research centers. Research areas were primarily the evaluationof all possible risks within one categoryof energysupply like nuclear ?ssion or fusion or fossil fuels and, even more important,the comparisonof risks of different energy-supplystrategies. Later on an independent program was started which still exists today under the name Risk and Vulnerability. There is a large amount of literature on risks to which IIASA’s research programs have contributed signi?cantly over the years, and there is, of course, an abundance of published work on international negotiations, part of which is a result of the work of the Processes of International Negotiation (PIN) Program. There are, however, so far no studies on the combination of these two strands. Therefore, and as research on both topics is housed at IIASA, we are happy that our PIN Program has undertaken the dif?cult and important task of analyzing what the editors of this book have called negotiated risks.