A disaster may be defined, for this paper, as “a situation in which an urgent need arises for international assistance to relieve humansuffering.” Disasters are frequently divided into manmade and natural disasters. Many so-called natural disasters have, however, a considerable manmade component in their etiology. The number of people vulnerable to the effects of disasters is increasing, and in the future disasters affecting human beings are likely to occur with greater frequency and severity, Full account must also be taken of the effects of a rapidly expanding world population, of advances in science and technology, and of economic and ecological factors.