This book contains the papers delivered at the Fourth International Symposium on Intracranial Pressure, held at Williamsburg, Virginia, USA, June 10-14, 1979. Divided into 12 sessions, they reflect the most recent developments in areas such as head injuries, pressure volume studies, cerebrovascular complications, intracranial hemor rhage, brain edema, systemic factors and infectious processes, data recording and analysis, CSF formation and absorption, hydroce phalus, clinical aspects of ICP monitoring, anesthesia and intra cranial pressure, treatment with barbiturates and steroids, and os motherapy. The book concludes with a summary of the present state-of-the-art in the field as a whole by Dr. Langfitt. There were two innovations at this Symposium. The first of these was poster sessions, the second, breakfast seminars. This volume contains all papers read plus all those presented as posters, and for this reason contains more pages than the three previous volumes. The organizers wish to thank the Advisory Committee for the work done in paper selection and focus of the Conference. Appreciation is also given to the Chairmen and Co-chairmen of the sessions for the preparation of summary statements. Manuscript preparation was performed by Ms. Lucille Browne, and gratitude is expressed to her. The next Symposium, the Fifth International Conference on ICP, will be held in Japan in 1982. We also wish to acknowledge the technical help of Springer-Verlag and their celerity in producing this volume. The Editors VII Contents Session I. Head Injury Chairman: D. P. BECKER; Co-chairman: I. PAPO 3 Summary … … … ….