A distinction between primary and secondary brain damage of vari ous origin, particularly in acute lesions, such as head injury and ische mia is not entirely new. The concept is of practical significance, be cause it is the foremost intention of all clinical efforts to prevent, or at least attenuate the development of secondary sequelae. Primary dam age to nervous elements usually cannot be influenced by treatment. Its prevention is the objective of prophylactic measures. The current volume gathered prominent scientists and clinicians from various fields to pro vide a competent introduction and survey of the various aspects involved in secondary brain damage. It was attempted to provide criteria for the distinction between the primary and secondary phenomena on a morpho logical and functional level, on the basis of the kinetics involved and, most importantly, regarding the different specific manifestations, such as disturbances of microcirculation, aspects of the blood-brain barrier, and of cellular structure and function at a molecular level. Although it was not expected that a grand unifying hypothesis will be reached recon cilable with the many, occasionally opposing views on such a complex subject, nevertheless, the present volume attains an appropriate result. It can best be described as a mosaic of many different pieces which only as an ensemble reflect the current state of the art.