The concept of the archetype - a concept first made famous in the modern era by the medical psychologist Carl Gustav Jung - is, as the term expressly indicates, a predisposed type. The type in question, the predisposing psychological and psychiatric type, as well as its underlying biology, is the subject matter of the present work Biology of the Archetype. While the psychology of the archetype and the many formal considerations attending it were treated by Jung in very considerable detail, the biology of the archetype was treated by him to a much lesser degree, and the situation has not changed appreciably since. Some efforts in the field of evolutionary psychology and psychiatry have proven productive in this regard, having successfully identified much of the evolved behavioral biology underpinning the archetypes; but what has been conspicuously missing, and what this work principally addresses, is the neurobiology of the archetypes. This work represents the first volume of a two volume set. The companion volume, which addresses the relationship of the archetypes' neurobiology to the psychology and psychiatry of the archetypes, as well as the implicated mental disorders, is forthcoming.