This textbook for university students gives definitions of emergencies, crises and disasters (earthquakes, mudslides, fire, floods, drought, pollution, deforestation, epizootics, epidemics, meteorological , and technological disasters). It describes how to manage crises and risks, pre-hospitalization and care phases and how the main clinical entities are distributed for the treatment of the various crises (explosions, crushes, ...). (UNEsCO)