Our inferences from our studies are these: man's relation to his social environment as perceived by him has a profound effect upon his general health. It influences the development and progression of all forms of illness, regardless of their nature, and regardless of the influence of other etiological factors. Its effect often far outweighs the influence of changes in the physical environment and the effects of random exposure to pathogenic or noxious agents. As a group, those who are experiencing difficulty in adapting to their social environment have a disproportionate amount of all of the illness which occurs among the adult population.