The view is presented that integrative therapies require a theoretical foundation in order to be more than a hodgepodge of eclectic techniques. Integrative therapy is considered as a logical derivative of a mature clinical science that must (1) embody conceptual theories from which propositional deductions may be derived, (2) lead to the construction of a coherent taxonomy for the subject domain (here personality disorders), (3) possess a variety of empirically oriented instruments that can identify and quantify taxonomic constructs, and (4) produce change-oriented intervention techniques consonant with both the given theory and the integrative root metaphor of the personality itself. Personality is described as a multireferential construct. A domain-specified model of assessment and a polarity-oriented model of therapy based in evolutionary theory are advanced. It is argued that optimal integrative therapy must proceed through “catalytic sequences” and “potentiating pairings” of domain-oriented (e.g., behavioral, cognitive, interpersonal) therapeutic techniques. These sequences and pairings are guided by an overall theoretically based integrative understanding of the client.