Abrams examines psychological transformations—the progressive differentiations of constituent elements of the psyche which become integrated in increasingly complex organizations. Experiences are organized as hierarchical phase organizations. These are complex structures that mediate psychological function, which is thus experienced as continuity in the midst of discontinuity. Development, a matter of transformation rather than linearity, is characterized by regression, arrest, and overlap of phase organization. Abrams reconsiders the major psychoanalytic developmental theories in terms of scope, focus on constitutional or environmental aspects, approach to defining developmental phase sequence, type of observational data systematized, and level of abstraction of that data.