The association between social class and psychiatric disorder has been one of the central topics of socio-epidemiological research since its inception. With remarkable consistency, numerous investigations have demonstrated an inverse correlation between social class and prevalence rates for most forms of psychopathology. The debate on the interpreta­ tion of these findings - social causation versus social selection processes - continues to this day. Moreover, the question as to what the psychoso­ cial processes are through which social class and individual psychopa­ thology are mediated has remained mostly unanswered. The concept of social stress may well provide new insights in this regard. One should note, in particular, the considerable conceptual and methodological progress made in life event research. Recently, the first attempts have been made to link the two concepts of social class and social stress. These developments will be retraced in this book in the light of new investigations. Descriptive epidemiological studies on the relation between social class and psychiatric disorders form the point of depar­ ture. Explicit reference is made to two classical studies in psychiatric epidemiology: Faris and Dunham's Chicago study and the New Haven study by Hollingshead and Redlich. Following on from there, various approaches in analytical epidemiological research are presented which attempt to determine whether - or, more precisely, to what extent - social causation or social selection processes can be said to be responsible for the higher rates of psychiatric disorders in lower social strata.