Normal and abnormal personality development can be quantified in terms of 15 specific steps in the self-organization of character as a complex adaptive system. Character is measured as three dimensions of Self-directedness, Cooperativeness, and Self-transcendence, each with five components corresponding to steps in personality development. Each of these steps is differentially influenced by heritable temperament dimensions, antecedent steps in character development, and life experiences. Predictions about the nonlinear dynamics of personality development, such as equifinality and multifinality, are confirmed in longitudinal data about individuals representative of the general population. The stepwise development of character determines large differences between individuals in their risk of psychopathology, as well as varying degrees of maturity and health.