This book deals with methods that individuals use to feed information and opinions back to mass communication systems. Typical examples of mass media and "information centers" were used to study feedback and environmental adjustment. Specifically, the feedback channels investigated are letters to the editor in newspapers, the urban newspaper ombudsman, the "call-in-your-opinion" shows on radio, and the information center accessible by telephone. Data collected in this study show that letters to the editor tend to serve advantaged classes and deal in content with issues not directly related to a specific newspaper article; users of the other feedback methods tend to react to specific, media-generated issues. With the volume of messages being emitted by the mass media, individuals on the reveiving end have difficulty with feedback, thus causing problems in "coping" or social adjustment. (CH)