The primary theme of this article, which serves as the introductory contribution of a special section of the "American Psychologist," is that work plays a central role in the development, expression, and maintenance of psychological health. The argument underlying this assumption is articulated at the outset of the article in conjunction with a historical review of vocational psychology and industrial/organizational psychology. The article follows with an overview of contemporary vocational psychology and a presentation of the psychology-of-working perspective, which has emerged from critiques of vocational psychology and from multicultural, feminist, and expanded epistemological analyses of psychological explorations of working. Three illustrative lines of inquiry in which research has affected the potential for informing public policy are presented. These three lines of scholarship (role of work in recovery from mental illness; occupational health psychology; and working, racism, and psychological health) are reviewed briefly to furnish exemplars of how the psychological study of working can inform public policy.