Systematic treatment selection (STS; Beutler &. Clarkin, 1990; Beutler, Clarkin, & Bongar, 2000) is an empirically developed procedure for identify-ing the mix of therapist, treatment strategies, and psychotherapeutic inter-ventions that are most likely to produce a favorable response in any given patient. Two basic assumptions underlie this approach: (a) There is no treat-ment method or model that works well on all patients, and (b) most treat-ment methods work well on some patients (e.g., Beutler & Harwood, 2002; Howard, Krause, & Lyons, 1993). The effects of most (if not all) treatments range from very positive to mildly negative, depending on the patient ob-served. STS seeks to identify which patients will respond positively to vari-ous mixes of interventions from different treatment models. Treatments are not mutually exclusive, however. Regardless of whether they are identified (e.g., by similar labels or brands), treatments are distinguished more by the pattern of interventions used than by the exclusivity of the procedures used (e.g., Malik, Beutler, Gallagher-Thompson, Thompson, & Alimohamed, 2003). Moreover, the procedures used are more closely related to the therapist's training and beliefs than to the procedures' scientific validity (Beutler et al., 2000). 29 Contemporary efforts to construct research-informed guidelines do not as a rule address the commonalities among treatments; practitioners prefer instead to think of each treatment model as a discrete and identifiable entity that can be applied to all patients with the same diagnosis. However, the presence of a shared diagnosis occludes the presence of important differences among patients. Thus, the appropriateness of any given treatment model de-pends both on the pattern of interventions used and the fit of these interven-tions to both the diagnostic and nondiagnostic characteristics of the patient. In contrast to the broad approach of fitting a treatment model to a patient's diagnosis, STS seeks to identify the specific pattern of patient traits and states (dimensions) that best fit with a corresponding pattern of demand characteristics that constitute the amalgamation of a treatment strategy and a therapist's particular relationship style. Rather than identifying the treat-ment received by a patient purely in terms of the theoretical model that guides it (e.g., cognitive therapy, psychoanalytic therapy, interpersonal therapy) or the techniques that it contains (e.g., interpretation, thought records, evidence analysis), all of which may reveal more about a particular therapist's beliefs than about in-therapy behavior, STS is constructed around principles of behavior change—guiding theorems of change and relationship that cut across treatment models and theories and that can be applied by individual therapists from different perspectives (Beutler et al, 2000). In the strictest sense, STS is not an "integrative therapy"; it does not attempt to combine theoretical concepts or to derive a unified theoretical approach of any type. To the degree that it falls within the domain of current descriptors, it is a "technical eclectic" approach, but even that label is impre-cise because STS does not specify any particular set of techniques but rather allows the therapist to use procedures from any particular approach that are consistent with the application of cross-cutting principles of change and in-fluence (e.g., therapeutic change is most likely when the therapeutic proce-dures do not evoke patient resistance). The principles and applications of STS have been defined and devel-oped through a four-step process (Beutler et al., 2000). The first step was a series of literature reviews designed to identify predictors and moderators of therapeutic change. The second step was to collapse and combine these pre-dictors and moderators into a smaller set of clusters, each of which identified a particular fit or match between patient qualities and treatment strategies that reliably relate to change and improvement. The third step was to de-velop means for measuring the patient qualities and treatment strategies that emerged from the prior steps. The fourth step tested a series of hypotheses that had been extracted from the reviews of literature, all of which bore on the question of what factors accounted for optimal therapeutic change. A detailed review of these steps is contained in Beutler et al. (2000). The application of the original STS dimensions for the task of planning treatment is illustrated in the next section, as applied to the case of Frank, a 30 BEUTLER ETAL.