This volume contains papers presented at the Fifth International Symposium on Intra cranial Pressure held on May 30-June 3,1982, in Tokyo, Japan. The Symposium has continued to grow since it began in 1972, and this year it was comprised 121 oral and 46 poster presentations. This considerable number was chosen from the more than 216 abstracts that were received, which made the selection process very difficult. We would like to thank the Program Committee for their efforts. One hundred and fifty-one of the manuscripts are printed here. The classic papers, short communications, and the presentations for the poster sessions here appear together under their appropriate topic heading. There were eleven sessions which spanned the most basic scientific descriptions of ICP dynamics to the most recent clinical advances and debate. Also included are the seven special seminars given by the invited speakers. These spe cial seminars were an innovation at this symposium as a means of reviewing the major aspects and history and of projecting the future directions of this expanding field. The organizers wish to thank the Advisory Committee for their guidance and focus, and to express their appreciation to everyone who contributed to the success of this meeting - to the Chairmen and Co-chairmen, to all of the members and participants, and not least of all to our executive staff who worked behind the scenes. We also wish to acknowledge our gratitude to Springer-Verlag for their technical aid and for their prompt publication of this volume.