The fundamentally social nature of all living things has its origin in the physical relationship between parent and dependent offspring. The organism is a species of society and the solitary animal is, in any species, an abnormal creature. The tendency of living things to form societies is coeval with life itself. Examples of biological coöperation or biosocial facilitation are cited and are held to represent, among lower and simpler animals, earlier stages of the complex social life of higher animals. This principle of coöperation has great survival value and is as important if not more important than competitive struggle for existence and survival of the fittest. Coöperative and competitive principles actually operate simultaneously. These concepts are applied to an understanding of the biological and psychological situation of the