An Advanced Study Institute on the Biology of Aggression was held in glorious weather between the twenty-first and thirtieth of July 1980, at the Chateau de Bonas, Gers, France. The Institute was arranged by a scientific organizing committee consisting of Drs. Paul Brain and David Benton of the University College of Swansea, Wales, U.K. This book reflects the papers presented at the A.S.I., and the arrangement of the book parallels the pro­ gramme. The particular objective was to concentrate on recent research on aggression from the viewpoint of the diverse biological disciplines that have examined the topic. A major theme that emerged was the failure of direct reductionist approaches that look for simple relationships between biological variables and 'aggression'. As may have been predicted, there was also con­ siderable debate about the definition of the term aggression and its associated positive and negative implications. The organizers would like to express their appreciation to Professor and Madame Simon for their foresight in founding the Association Scientifique Cu1tu~e11e et Educative de Bonas and their enthusiasm in designing and converting the Chateau de Bonas to produce a unique conference centre, a venue that greatly facilitated this A.S.I.'s objectives. Greatfu1 thanks are also due to the Faculty who selflessly gave of their time; to Dr.