The development of psychological theory has always depended on efforts to empirically justify its hypothetical constructs and applied practices. But vis-à-vis applied practices, the pressure for justification has become increasingly strong. In the recent past, mandates that psychologists, psychiatrists, and other mental health professionals be accountable for their clinical actions have been issued repeatedly from both within our own ranks (e.g., Eysenck, 1952; Raimy, 1950) and by outside parties such as consumer protection organizations and insurance companies. Calls for accountability have been amplified with the realization that the practical value of psychotherapy is frequently less than had been assumed or implied. Indeed, over 45 years ago, Raimy (1950) pointed out that the basic features of acceptable science, including reliability, internal validity, and predictive validity, were lacking in clinical endeavors: “Psychotherapy is an undefined technique, applied to unspecified problems, with unpredictable outcomes” (p. 93). A primary reason for the decidedly unscientific status of clinical psychology and psychiatry five decades ago can be found in the wide gap that existed at the time (and continues to exist, though it is narrower) between basic research and applied clinical practice. Until Wolpe’s (1958) reciprocal inhibition procedure, no psychological treatment had its basis or origins in empirically generated findings. As a result, clinical work proceeded independently of laboratory efforts. Wolpe’s procedure was unique in two respects. First, his hypotheses were inductively formed through analysis of experimental data. As such, they contrasted with the hypotheses of contemporaneous psychodynamic theories, which were abstracted from clinical impressions. Second, effects (if not processes) of Wolpe’s treatment were predictable and measurable. Declarations of success or failure were made according to operationalized, observable criteria. Thus, for the first time, therapists were able to justify their actions and theories on the basis of data instead of inference. Psychotherapists, like practitioners of other therapeutic sciences (e.g., medicine), were in a position to account for their behavior.