This is a record of a conference devoted to the neurophysiology of some emotional changes produced by drugs. Among various problems the physiological concomitants of anxiety produced by injection of certain drugs were studies experimentally, with special reference to cerebral circulation. The changes of electrical activity in relation to anaesthesia were another subject of research. Among the participants in the symposium were psycho-analytically informed neuropsychiatrists and neurophysiologists (Grinker, Gerard, Mirsky). This book testifies to the seriousness with which the multidimensional and interdisciplinary approach is being pursued in the United States. Although symposia such as this have so far achieved no more than to throw into relief the difficulties of a synthesis, they are bound to prove fruitful by improving mutual understanding between all those concerned with research into mental functions.