First presented as lectures at the C.G. Jung Institute in Zurich, the two authors expand, each in their own way, upon Jung's famous theory of types: Introversion and Extroversion as attitudes; Feeling, Thinking, Sensation and Intuition as functions of the personality.

Hillman elaborates upon the feeling function and differentiates it from eros, from emotion, from femininity and suggests ways of its educations.

Von Franz, perhaps Jung's closest pupil and follower, brings many practical examples to show the ways in which the inferior, unadapted side of personality uses the four functions for better and worse in relationships, in work, and in the development of the psyche.