The past twenty-five years have seen considerable social science research on the risks of technologies and economic activities, and an even lengthier legacy of studies on natural hazards. This work has generated a substantial knowledge base from which to interpret such issues as the sources and causes of changing risks and the ways in which various groups and different societies assess, view, and cope with those risks. In particular, risk perception researchers have investigated in depth how judgments about perceived risks and their acceptability arise, and how such judgments are related to risk “heuristics” (e.g. the memorability, representativeness, and affective qualities of risk events) and the qualitative characteristics of risk (e.g. voluntariness or catastrophic potential). Patterns of risk perception have also been found to relate to both group and cultural affiliations. Meanwhile, dramatic events such as the Chernobyl disaster, the BSE (“mad cow”) and the genetically modified crops controversies in Europe, the September 11th attacks in the United States, and the prospect of global climate change have driven home to responsible authorities and corporate managers the extensive intertwining of technical risk with social considerations and processes. As Kai Erikson (1994) succinctly puts it, modern disasters present us with a “new species of trouble.”

These events and the growing knowledge base are changing the ways in which societies assess, respond to, and communicate about risks. In the United Kingdom in the early 1990s, the Royal Society Study Group on Risk had as a specific mandate the task of bridging the gap between scientific knowledge and “the way in which public opinion gauges risk and makes decisions” (Royal Society 1992, p. 1).