This volume is the first to describe all clinically and experimental relevant aspects of primary and secondary brain stem lesions important to clinicians. It contains a detailed description of the computer-tomographical and morphological changes of the cerebral cisterns in acutely and chronically increased intracranial pressure. The prognostic value of clinical parameters of primary and secondary brain stem lesions is demonstrated. The possibilities of assessing the clinical course by computer-aided evaluation are presented. In addition to that, comprehensive view of morphological, radiological and clinical findings, extensive investigation concerning blink reflex (BR) and auditory evoked brain stem potentials (BAEP) supply highly relevant functional aspects of those lesions. The effects of raised intracranial pressure upon BR, BAEP as well as upon cerebral blood flow and focal flow in different brain areas were studied in animal experiments and reveal new and fascinating conclusions. Based on these investigations, a mathematical model following modern concepts of system analysis was developed. The model includes the intracranial system, autoregulation of cerebral flow (cardiovascular components) and the short-time behaviour of arterial blood pressure regulation.