Since the beginning of my studies at the Madrid School of Medicine, I have been inspired by the memory of the Spanish histologist Santiago Ramon y Cajal and by his conception of the central nervous system, his penetrating advice about how to conduct scientific research, and his philosophical ideas about life and death. Sixty-five years ago, Cajal said that knowledge of the physicochemical basis of memory, feelings, and reason would make man the true master of creation, that his most transcendental accomplishment would be the conquering of his own brain.

My personal background is the usual rather specialized one of a biologist, but I have been compelled to venture beyond the limits of my science by the need to evaluate the experimental reality of motor behavior and mental phenomena directed by electrical and chemical stimulation of functioning brains. I have also felt the anxiety of our age, which requires a better understanding of the cosmological situation of man in order to give a rational and emotional purpose to human life; and I have been concerned by the urgent need to resolve archaic human antagonisms and to find a new conviviality based on biological reality rather than on wishful thinking. As T. M. Hesburg, president of Notre Dame University, has said, "Scientists cannot be neutral." We must understand the social responsibility attached to our research and the moral impact it has on the world of men, including ourselves. At least there is novelty

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in looking at behavioral manifestations not from outside the organism but from inside the spiking neurons where information is interpreted and responses are organized.

This book was begun during a sabbatical leave of absence from Yale University under a Guggenheim Fellowship. Part of its content was presented at the New York Academy of Sciences in December 1968 as Salmon Lectures. Dr. Paul Weiss' Rockefeller University evaluation of the preliminary manuscript was very helpful. Economic support for my research has been provided by grants from Foundations' Fund for Research in Psychiatry, United States Public Health Service, Office of Naval Research, United States Air Force 657 1st Aeromedical Research Laboratory, NeuroResearch Foundation, and Spanish Council for Scientific Education. The experimental material originating in my laboratory has been the work of a group of investigators from different countries to whom I express my warm appreciation. Their names are mentioned in our published work. Our most recent collaborators included Dr. Lembit Allikmets (Estonia, USSR), Dr. Humberto Bracchitta (Chile), Dr. Ronald Bradley (United Kingdom), Dr. Francis DeFeudis (USA), Dr. Taiji Hanai (Japan), Dr. Victor Johnson (United Kingdom), Dr. Diego Mir (Spain), Dr. Rodney Plotnik (USA), Dr. Maria Luisa Rivera (Spain), Dr. Chico Vas (India) and Dr. Jan Wallace (USA).

Ideas and reciprocal influences exchanged with my brothers, Rafael and Alberto, through the years have been important to the structuring of my own mind; the many enjoyable hours of discussion with my wife, Caroline, who has been a close, sensitive, and intelligent collaborator, have been decisive in the creation of this book.

The Salmon Lectures of the New York Academy of Medicine were established in 1931 as a memorial to Thomas William Salmon, M.D., and for the advancement of the objectives to which his professional career had been wholly devoted.

Dr. Salmon died in 1927, at the age of fifty-one, after a career of extraordinary service in psychiatric practice and education,

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and in the development of a world-wide movement for the better treatment and prevention of mental disorders, and for the promotion of mental health.

This volume in World Perspectives had its original source in the invitation extended to me in 1963 by Dr. Ruth Nanda Anshen to write a volume for World Perspectives Series which she plans and edits. The Salmon Lectures I gave in 1968 were based on the text of a part of this volume. José M. R. Delgado, M.D.