Erich Neumann
Author: Erich Neumann
Publisher: Princeton University Press (1954)

The development of personality proceeds in three different dimensions.  The first is outward adaptation, to the world and things, otherwise known as extraversion; the second is inward adaptation, to the objective psyche and archetypes, otherwise known as introversion.  The third is centroversion, the self-formative or individuating tendency which proceeds within the psyche itself, independent of the other two attitudes and their development.