As modern science and medical technology increase the life span of man, the human skeleton is required to function for longer periods of time. Many skeletal problems that besiege the adult stem from abnormalities that exist during infancy and adoles­ cence. These may be congenital problems or acquired problems due either to a child's environment or to some injury sustained during the growth years. Adolescents today are extremely active; many sports and hobbies subject them to an infinite array of traumatizing episodes that may result in injuries and diseases. When I wrote the first edition of The Adolescent Spine in 1976, I felt it pertinent to produce a work which would help medical students and practitioners alike. That edition was extremely successful, not only in this country, but also in many foreign countries. For a medical text, the number of copies purchased was overwhelming­ certifying that the adolescent spine is of serious interest to pediatricians, orthopaedists, physical therapists, physiatrists, medical students, and other allied health practitioners. This new edition has been revised and considerably expanded with this audience in mind. Four chapters have been contributed by authorities with special expertise.

In 1968 we reported that the hippocampus of adrenalectomized rats takes up and retains 3H-corticosterone (McEwen et al. 1968). This and subsequent studies, which were intended to identify and localize sites of adrenal steroid feedback in the central nervous system in terms of putative receptor mechanisms, were stimuli for a variety of investigations into the role of the hippocampus in adrenal steroid feedback on ACTH secretion and on behavior. In this respect, the identification of putative receptor sites was the impetus for the search for the function of glucocorticoids in hippocampus and

The Symposium on the Neural Basis of Behavior, from which this volume was produced, was held at the Alfred I. duPont Institute on June 7 and 8, 1979. It brought outstanding investigators in four fundamental areas of behavioral neurobiology into juxtaposition, there to provide an integrated, multidisciplinary perspective on behaviorally significant brain mechanisms. Particular emphasis was placed on topics of interest to neurobiologists as well as to clinicians in neurological and psychiatric disciplines. The session on central activity states was selected as an appropriate point of departure because the continuum of brain activity states extending from the natural depression of hibernation through the heightened levels of arousal accom­ panying learning is such a clear and basic determinant of behavioral output. The papers on learning and memory outlined diverse approaches to un­ derstanding the basis of these interrelat~d CNS capabilities that constitute the neural basis of behavioral adaptation. Finally, the topics of affective states and mechanisms of pain provided a focus of clinically relevant discus­ sion covering multiple levels of functional and anatomical CNS organiza­ tion.

At the request of a Subcommittee of the United States Senate, in February, 1975, the National Institute of Neurological Disorders and Stroke (now the National Institute of Neurological and Communi­ cative Disorders and Stroke) conducted a Workshop on the Research Status of Spinal Manipulative Therapy. The Workshop was held in response to the Senate Subcommittee's request for an "independent unbiased study of the fundamentals of the chiropractic profession. " Since spinal manipulative therapy is a key tenet of chiropractic, the Institute felt a research workshop focused on that issue would provide a useful base upon which to examine the broad concept of the role of biomechanical alterations of the spine in health and disease.

It is a privilege and pleasure to write a foreword to this work. Who, twenty years ago, would have thought that a whole book could be devoted to the veins of the posterior fossa? Even today the standard text-books of anatomy only give a paragraph to the subject. Thanks to the dedicated work of rather a few neuroradiologists our knowledge has now reached a very sophisticated level. The careful correlation of anatomical dissection with the angiographic image has achieved this, but without the aid of subtraction (discovered by a world figure in neuroradiology - Professor ZIEDSES DES PLANTES) the subject would not be as advanced as it is. The authors are to be congratulated not only for presenting the most up to date anatomical information but also for showing how wide the applications are in the clinical field by the careful analysis of displacements of veins, many of which were quite unrecognised only a very few years ago. Drs W ACKENHEIM and BRAUN are in the forefront of this discipline to which they and the French school have contributed so much. Also it was their great enthusiasm and drive which led to the birth of the European Society of Neuroradiology, the first meeting of which was held in Colmar in September 1969. The Society has flourished under their guidance and very successful annual meetings have been held for nearly a decade.