Concluding this book with a review of Jung's concept of psychic energy is apt for several reasons. It is central to Jung's description of symbol formation, though neglected in contemporary Jungian studies, and Jung himself stopped developing the concept after the 1920s. His `®nal word' in that regard is a 1928 essay, `On psychic energy' (CW 8). From 1912 onwards, Jung presented his concept as an amendment of Freud's theory, though it is radically different:

By libido I mean psychic energy. Psychic energy is the intensity of a psychic process, its psychological value. This does not imply an assignment of value, whether moral, aesthetic, or intellectual; the psychological value is already implicit in its determining power, which expresses itself in de®nite psychic effects. Neither do I understand libido as a psychic force, a misconception that has led many critics astray.