Cognitive-experiential self-theory (CEST) is a broadly integrative theory of personality that is compatible with a variety of other theories, including psychodynamic theories, learning theories, phenomenological self-theories, and modern cognitive scientific views on information processing. CEST achieves its integrative power primarily through three assumptions. The first is that people process information by two independent, interactive conceptual systems, a preconscious “experiential system” and a conscious “rational system”. By introducing a new view of the unconscious in the form of an experiential system, CEST is able to explain almost everything that psychoanalysis can and much that it can not, and it is able to do so in a scientifically much more defensible manner. The second assumption is that the experiential system is emotionally driven. This assumption permits CEST to integrate the passionate tooth- and-phallus unconscious of psychoanalysis with the “kinder, gentler” affect-free unconscious of cognitive science (Epstein, 1994). The third assumption is that four basic needs, each of which is assumed in other theories to be the one most fundamental need, are equally important according to CEST.