The first International Symposium on Brain Edema was organized by Dr. Klatzo and Dr. Seitelberger and held in Vienna in 1965. The second Symposium was held in Mainz in 1972 and organized by Dr. H. J. Reulen and Dr. K. Schiirmann, the third in Montreal in 1976 by Dr. H. M. Pap- pius, the fourth in Berlin in 1979 by Dr. J. Cervos-Navarro, and the fifth in Groningen in 1982 by Dr. K. G. Go. This volume contains the papers presented at the 6th International Sym- posium on Brain Edema, held in Tokyo, Japan, November 7-10, 1984. The invited lectures by Dr. I. Klatzo, Dr. A. Hirano, Dr. S. I. Rapoport, Dr. B. K. Siesj6, Dr. H. M. Pappi us, Dr. K. A. Hossmann, and Dr. D. M. Long are included as special chapters. On behalf of the organizing committee, I wish to express my deep ap- preciation to all the participants for their contribution toward making this meeting so fruitful and significant. Moreover, the great success of this Sym- posium depended on the high quality of the invited lectures and presen- tations by experts in various fields, as well as on the free and enthusiastic discussion. I was deeply impressed with the papers presented by all the authors, who endeavored to elucidate their subjects. The editors have made only minor corrections and rearrangements, since prompt publi- cation was considered to be important.