Publisher Summary The logical empiricist philosophy of the kind that has dominated traditional thinking about psychological research placed a strong emphasis on the relationship between theoretical statements and observation. It is essential to deal with the place of empirical data in evaluating the progress of inquiry. The traditional crucible for assessing inquiry into self is considered empirical. It sets the stage for tracing major evolutions in understanding within the present renaissance of self-inquiry. In the theory of the self, particular attention is given to (1) the concept of self-knowledge, (2) the concern with the self as agency, and (3) the shift from structural to process orientations. Alterations in these domains together suggest a major evolution in the dominant image of human functioning in social psychology. The limitations of the concept as a theoretical implement and means of moving beyond existing barriers in future undertakings are also discussed in the chapter.