Michael E. Addis, Ph.D., is associate professor of psychology at Clark University in Worcester, MA. For several years, he has served as a clinical supervisor and trainer of therapists conducting behavioral activation treatments for depression. He received his BA from the University of California, Berkeley, in 1987, and his Ph.D. from the University of Washington in 1995.

He has published over forty scientific articles and books on a range of topics including the treatment of depression, the relationship between research and practice in clinical psychology, and men's mental health. He is past recipient of the President's New Researcher Award from the Association for the Advancement of Behavior Therapy. In 2003, He received the researcher of the year award from the Society for the Psychological Study of Men and Masculinity, and the American Psychological Association's David Shakow Award for early career contributions to the science and practice of clinical psychology Christopher R. Martell, Ph.D., ABPP is clinical associate professor of psychology at the University of Washington in Seattle, WA, where he also maintains a private practice. He is board certified in clinical psychology and behavioral psychology by the American Board of Professional Psychology and is a founding fellow of the Academy of Cognitive Therapy. He is first author of the books Depression in Context: Strategies for Guided Action and Cognitive Behavioral Therapies with Lesbian, Gay, and Bisexual Clients.

He has published articles and book chapters on behavioral treatments for depression, couples therapy, and issues affecting gay, lesbian and bisexual individuals. He is past president of the Washington State Psychological Association. He has conducted professional workshops on behavioral activation treatment for depression in the U.S. and Internationally.