H aving read, lauded, and concurred with Fuertes and Williams's (2017) call for more client-focused psychotherapy research, we eagerly agreed to contribute this chapter on clients' own views of psychosocial treatment outcomes and their mechanisms. That said, we also appreciated the inherent challenge in identifying this chapter's unique and complementary scope within the overall volume. In its broadest sense, client-focused psychotherapy research could conceivably cover any outcome construct or variable that pertains to the client (whether defined by researchers, therapists, or clients), with data collected in any number of ways. After having recently contributed a comprehensive review of the research on the client, therapist, and relational factors to Bergin and Garfield's Handbook of Psychotherapy and Behavior Change (seventh ed.; Constantino, Boswell, & Coyne, 2021), we were acutely aware of how vast and unwieldy a review of "all things client related" could get! However, to us, truly client-focused outcome research requires more than an examination of any inherently client-related factors that change or predict change. Rather, such research needs to explicitly draw out and privilege the client's voice or narrative to understand these primary outcome-related elements. To draw on McLeod et al.'s (2009) rubric of stakeholder positions, such focus reflects user-constructed outcomes and their mechanisms, as opposed to researcher-or therapist-constructed outcomes and mechanisms. Accordingly, we discuss herein research that has, in both content and method, directly asked adult clients (this age criterion is consistent with the volume's overall