Book excerpt: In this book current knowledge of the pathophysiology of shock, sepsis and multi organ failure is presented. The rapid progress which has been made and the results achieved in intensive care medicine are based on sound basic research, which is duly reflected in these chapters. Multiorgan failure is the foremost cause of postoperative and posttraumatic death and many complex mechanisms are involved. Only with a good foundation of basic research can abnormalities in the physiological, biochemical, and morphological course of shock be recognized and the necessary conclusions for treatment drawn. Therapy must proceed from profound knowledge of the multi variant physiological events in order to influence shock, sepsis and organ failure. Although numerous possibilities for therapy have arisen from pharmaceutical research in recent years, they are beyond the scope of this book and are not discussed here. To gain a better understanding of the pathophysiological events it was necessary to examine and to describe different models that simulate and reproduce these events. Here we describe the causative agents (shock) and the consequences (sepsis, organ failure) in two main sections, divided on the basis of their pathophysiology.