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...