Acceptance and Commitment Therapy (ACT) is one of a 'new-wave'of acceptance-focused behaviour therapies. Proponents of ACT argue that it is worthy of the attention of those interested in behaviour change through psychotherapy, for four reasons. 100 The literature review discusses these reasons. First, ACT is based on the philosophy of functional contextualism, which, it is argued, is consistent with the natural analytic agenda Cý of clinicians. Second, ACI'offers a broadly applicable theory of psychopathology. The theory holds that much psychopathology results from experiential avoidance- efforts by a person to avoid, change, and/or otherwise control difficult private experiences (e. g., emotions, thoughts, memories, bodily sensations). ACT is a treatment for experiential avoidance, in which clients are guided toward willing acceptance of private experiences, in the pursuit of their values. Third, four empirical studies provide evidence for the usefulness of ACT as a treatment approach. This evidence is critically evaluated. Fourth, ACT has been used to treat many different topographically defined psychological problems and may be applicable to others. ACT is a promising treatment approach that requires further empirical investigation. The research study describes the application of ACT to the treatment of experiential avoidance in two adolescents with disruptive behaviour problems (DBPs). There are a number of reasons to believe that experiential avoidance may be an important functional factor in this population. It was hypothesised that treatment would result in clinically significant decreases in participants' (a) self-reported experiential avoidance, and (b) parent-reported frequencies of DBPs. Single-case experimental methodology was