Posttraumatic cerebral contusions, lacerations and hematomas in the past could often only be suspected by clinical symptomatology and be visualized by angiography in a restricted manner, but they are now diag- nosed with precision through CT and MRI; they remain in the limelight in our daily management of severe head injuries. Stalhammar’s longlasting research in biomechanics is he re condensed in a concise review of the current knowledge in this field, thus providing the basis for our understanding of the parenchymal cerebral posttraumatic lesions. The neuropathological investigations and findings remain fundamental to the clinical features, and in this text there is the advantage that they were carried out and interpreted by a very experienced neurasurgeon, Ion Oprescu, who most regretfully died before the completion of this volume. The special morphological and clinical investigations by Nakamura, concerning diffuse brain injury, contribute to our necessary diagnosis and treatment of this phenomenon where, without grass visible lesions of cerebral tissue, a high mortality occurs. The clinical features, the princip1es of therapy and the outcome are described by Vigouroux and Guillermain, whose clinical study clearly demonstrates the limitations of all our efforts in severe brain injuries, in spite of decades of clinical experience and research.