Cognitive Behaviour Therapy (CBT) research has primarily focused on the reduction of negative symptoms as evidence for the effectiveness of the psychotherapy. However, positive factors such as Qualify of Life (QOL) have been largely ignored. Clinicians have only recently begun to incorporate QOL assessment into their treatment protocols and outcome studies, and very few longitudinal studies have been reported in the literature. This book presents a series of studies which demonstrate that subjective QOL is a valid and important outcome to consider in clinical practice with patients who struggle with anxiety and depressive disorders. We demonstrated that Group CBT was effective for treating psychiatric hospital outpatients with anxiety and depression, with improvements in both symptoms and QOL at post-treatment, which were maintained at long-term follow-up. We concluded that positive factors such as QOL were important outcome variables that must be monitored in clinical practice and research when determining the effectiveness of psychotherapy.