The authors of this book were chosen with an emphasis on workers in preclinical or "basic" medical sciences as opposed to clinicians. Ten of the authors are chemists, six physiologists, five psychiatrists, four neuropathologists, three anatomists, three psychologists, two geneticists, one internist, one epidemiologist, and one electroencephalographer. Both the effectiveness and weakness of the book are associated with the diverse assemblage of experts in related fields who bring together data obtained with different techniques but with the same general goal. The avowed purpose of the conference and symposium was discussion of "cross fertilization," which Gerard, in the final chapter, considers as "good clean fun [which] keeps us going..."; however, the topic is sometimes overworked nowadays. The symposium consists of 38 chapters, each of which usually represents the contribution of several authors. Half of the presentations are concerned with the biology of mental health and half with biological aspects of mental