Schachtel shared with his great contemporary David Rapaport the goal of scientifically reframing the psychoanalytic understanding of personality. first published in 1966, is in one sense Schachtel's extended dialogue with Rapaport (in the guise of Schachtel's interlocutor) about this ambitious task. In the course of his brilliant and lucid meditation on this topic, Schachtel attempted far more than the simple explication of particular test responses. His book contains, and should be read as, an entire theory of personality considered in terms of the ways in which one person may meaningfully and detectably differ from another.