Georg H. Eifert, Ph.D., is professor and chair of the department of psychology at Chapman University in Orange, CA. He was ranked among the top thirty researchers in behavior analysis and therapy in the 1990s, and he has authored over 100 publications on psychological causes and treatments of anxiety and other emotional disorders. He is a clinical fellow of the Behavior Therapy and Research Society, a member of numerous national and international psychological associations, and he serves on several editorial boards of leading clinical psychology journals. He is also a licensed clinical psychologist. He is coauthor of Acceptance and Commitment Therapy for Anxiety Disorders and ACT on Life, Not on Anger.

John P. Forsyth, Ph.D., is a scientist, writer, and licensed clinical psychologist in Upstate New York. He has traveled the world giving talks and workshops to the public and professionals about the benefits of mindful acceptance, kindness and compassion, and how to live a valued life using a new approach to psychological health and wellness called Acceptance and Commitment Therapy (ACT). He is Associate Professor of Psychology, Director of the Doctoral Training Program in Clinical Psychology, and Director of the Anxiety Disorders Research Program at the University at Albany, State University of New York.

Foreword writer Steven C. Hayes, Ph.D., is University of Nevada Foundation Professor of Psychology at the University of Nevada, Reno, and author of numerous books, including Acceptance and Commitment Therapy, Relational Frame Theory, and Get Out of Your Mind and Into Your Life, as well as hundred of articles and book chapters on related subjects.