Jennifer Gregg, PhD, is a psychologist, author, professor, and trainer. She is a professor at San Jose State University, and has spent twenty years treating cancer patients and their families. Gregg has been studying, delivering, and evaluating ACT since 1995, and she has published dozens of research papers, book chapters, and articles on ACT. She is coauthor of Stop Avoiding Stuff and The Diabetes Workbook.
Glenn M. Callaghan, PhD, is associate professor of psychology at San Jose State University and a member of the Association for Behavioral and Cognitive Therapies and Western Psychological Association. He is an internationally recognized expert in functional analytic psychotherapy and functional assessment methodology.
Steven C. Hayes, PhD, is Nevada Foundation Professor in the department of psychology at the University of Nevada, Reno. He has been president of numerous professional organizations, is author of forty-five books and nearly 650 scientific articles, and is among the most cited living psychologists. He has shown in his research how language and thought leads to human suffering, and is originator and codeveloper of acceptance and commitment therapy (ACT): a powerful therapy method that is useful in a wide variety of areas; relational frame theory (RFT): an empirical program in language and cognition; and process-based therapy (with Stefan G. Hofmann).