1. As in Manhattan the prevalence of psychiatric symptoms in the general population of this rural area is higher than one might expect, with only 17% of adults free of all symptoms of psychiatric significance. About a third of the population shows significant impairment from psychiatric disorder, while twenty-plus percent stand in need of some sort of psychiatric attention.2. The amount of disorder differs with the biologic variables of age and sex. Except in the disintegrated communities, women tend to show more psychiatric disorder than men though the proportion with significant impairment is approximately the same. Older people tend to show more than younger people until they reach 70 years or so.3. Considering the 1010 county survey respondents as a whole, our indicator of social class showed what has been found in other studies, namely that better mental health is associated with higher social class. This relationship could not be demonstrated, however, in the largest town in the county.4. Intensive studies of communities that are polar with respect to level of social integration showed a far stronger association of better mental health with higher level of integration than with higher social class within these communities.5. It is not poverty or limited education or lower class status, per Se, that makes the difference to mental health, but rather a whole group of factors that tend to be associated with these and that create a social environment that lacks features that are vitally important to mental health. To improve mental health, economic resources must be mobilized up to a point, education must be provided up to a point, but this will not be enough unless these factors bring with them the other environmental forces which add up to giving the individual the feeling that he is a worthwhile member of a worthwhile group.Something like this is probably the most important contribution of such endeavors as Hull House or the Peckham Experiment, which by various means served to re-integrate the social environment for many of their patrons.