This article is an extension of a previous paper by Allport who reviewed the many contemporary concepts of the ego. Bertocci's principle contribution is the development of a concept of the 'psychological self' which will help '(1) to understand the close functional relationship between ego, personality and self, and (2) to explain the possibility of continuity, succession, and interaction within the personality-ego systems'. The three concepts of self, ego, and personality are generally defined, interrelated and also contrasted. The unique adjustments that a 'self' makes with regard to its particular needs constitute the personality, whereas the ego is the self's evaluation of its activities. The concept of the psychological self is not, as the author admits, a hypothesis which one might attempt to verify directly by experimentation. It is offered as an aid to understanding and interpreting human experience.