Book excerpt: When an accident involves many people and when its consequences are many and serious, we speak of a disaster. Disasters have the same causal fac tors as accidents: they differ from accidents by the gravity of consequences, not by causes. The action of a single individual may result in thousands of deaths and huge financial losses. The metal fatigue of a screw may, by a chain of events, cause an explosion killing hundreds or lead to a break in a dam and a devastating flood. The fact that minor and unpredictable acts can lead to disasters is im portant because it allows us to predict that the years to come will bring with them more disasters with ever more severe consequences. The density ofhu man populations is growing. By the year 2025 some four fifths of the world's population will be living in urban settings. An explosion or a gas leak in a densely populated area will cause incomparably more damage than a simi lar event in a rural area. Modern technology is immensely powerful (and its power is continuing to grow) and can be used in a disastrous manner. Ag gression is just as possible now as it was in the past, but the tools of aggression are vastly more dangerous than ever before. This book, edited by Johan M. Havenaar, Julie G. Cwikel, and Evelyn J. Bromet, is therefore very timely.