The present revision is a cooperative undertaking of five members of the Anatomy Department of Columbia University College of Physicians and Surgeons. They have kept before them the fundamental idea that this was to be a textbook for students rather than a source book for teachers and research workers. They have endeavored to discuss the physiologic significance of the numerous structures described. The various revisers were assigned to those chapters in which they are most interested. The chapter on the central nervous system, written by Dr. Oliver Strong, which was revised in the last edition, remains unchanged. Some chapters have been entirely rewritten and many others have been brought down to date. This edition is well illustrated and a few of the illustrations are in colors.