A survey of human stereotypes that have probably existed in all human societies and therefore must have adaptive significance and be inheritable. Some are considered disorders when they contribute to maladjustment in highly regimented and complex modern societies. However, it is argued here that these traits (e.g. bipolarity, social awkwardness, reclusiveness) would not persist if they did not contribute to the survival of the species and should therefore be valued and accommodated whenever possible. The basic human group, assumed to consist of approximately 150 individuals, is described, with a proposed ideal number of individuals for each of the essential stereotypes. Parallels in the animal kingdom are also briefly discussed. This book is not a scientific treatise. Rather, it is essay by an amateur who argues for a greater acceptance and understanding of personality diversity as an adaptive feature of the human species. Jasper Burns is the author and illustrator of more than 40 books on a wide variety of subjects, including human and natural history, numismatics, and spirituality.