Neither cognitive psychology nor psychoanalysis has developed a comprehensive theory of affects. Such a theory of affect, integrating conceptions derived from Arnold, Lazarus, Tornkins, Bowlby, and Langer, is outlined. Affect is viewed as the subjective experience of feed back appraisal processes operating as part of motivational systems. Quality and intensity of affect are determined by the characteristics of the underlying motivational system and by the degree, direction, and rate of change of mismatch. Examples of motivational systems and their associated affects are given and the role of affect in cognitive development, as well as perception, are considered. By examples, the clinical application of these concepts is shown to avoid false leads and permit development of more effective clinical approaches.