Regression is a concept involving developmental as well as structural considerations. Clinically speaking, it refers both to psychopathology and to potentially therapeutic phases of the psychoanalytic process. Regression, a movement backward, reverts to more or less primitive stages of psychic organization which deviate from a norm, while at the same time these stages are enduringly active in the continual integration of psychic life. Regression and progression are necessary and complementary phases of this organizing activity. Certain theoretical and clinical aspects are discussed in some detail. The normative implications of regression, in the context of modern Western rationality as the standard of normal mental life, are briefly considered.