Presents a short biography of the 2012 winner of the American Psychological Association's Award for Distinguished Professional Contributions to Applied Research. Leslie S. Greenberg is an exemplary scientist-practitioner whose pioneering work has significantly altered the landscape of the field of psychotherapy research and practice. His seminal research program has addressed basic questions regarding the significance of empathy, the therapeutic alliance, and emotion in human functioning. Greenberg's sophisticated task-analytic research method, used to empirically test processes of change occurring within psychotherapy, has allowed researchers to build models of how people in individual therapy resolve self-criticism, let go of unresolved anger and hurt from past emotional injuries, and resolve conflict in marital therapy. Greenberg has made a substantial impact through the development of a new therapeutic approach called emotion-focused therapy, an evidence-based treatment for both depression and couples' distress. Greenberg's Award citation and a selected bibliography are also presented here.