This chapter resonates strongly its emphasis on the positive features of the patient's repertoire and not just on pathology. A key impetus in the evolution of psychotherapy integration was the finding by a range of psychotherapy researchers that there was surprisingly little difference in the outcomes of nominally quite different kinds of therapies. The idea of assimilative integration is, one might say, an essential corollary of postmodern thinking. The chapter then reflects by the prominence of the interpersonal contribution to what a number of the authors describe as the interpersonal-relational movement. The concept of multiple self-states has been increasingly prominent in relational thinking over the years and by now could well be listed among the defining characteristics of the relational point of view. As Arnkoff and Glass describe, rationalist and constructivist versions of cognitive and cognitive-behavioral therapy differ in philosophy of science, in theories of psychopathology and change, and in some important clinical aspects.