This volume contains studies of one particular category of risky situations, namely, those involving highly negative consequences with low probabilities. Situations of this type involve both natural and man-made disasters (e.g. floods, technological hazards, economic crises, epidemics, etc.). Such risks are characterized by two features: (1) they occur relatively rarely (the probability of their occurrence is very low) and (2) they have extremely negative consequences (they are catastrophic). Such events generally cannot be prevented, but one can both try to anticipate them and undertake...