In writing our book we had in mind both practicing physicians and scientif­ ic personnel. We hope that the former will benefit from an analysis of clinical symptoms and changes in the morphological substrate which produce them, and that the latter will be interested in facts illustrating the resistance of nervous tissue to compression and displacement, and in our concept of the primary role played by blood supply in the functional disturbances of a deformed brain stem. Although only a short time has elapsed since the first edition of the book, it has been necessary to introduce a number of addenda and corrections into the present edition. The chapter "Roentgenological Manifestations of Brain Displacements," written by N. S. Plevako and Z. N. Polyanker, has also been expanded. We are glad that a competent publishing house such as Plenum Press has undertaken the American publication of the book; we offer our sincere thanks to Mr. George Onischenko for his excellent translation; and we express our gratitude to Mezhdunarodnaya Kniga, the Soviet Book Export Agency, in the person of Galina Aleksandrovna Khudozhnikova, for their cooperation.