Robyn D. Walser, PhD, is a clinical psychologist, educator, and author of several influential books on ACT for professionals and general readers. She is Assistant Clinical Professor at the University of California, Berkeley, and Director of Research at Bay Area Trauma Recovery Clinical Services. She is also on the staff of the National Center for PTSD at the VA Palo Alto Health Care System. Internationally known for her compassionate, client-centered approach, Dr. Walser has been working in the field of trauma treatment since the 1990s.

Darrah Westrup, PhD, is a clinical psychologist in private practice in Durango, Colorado, where she specializes in helping clients find freedom from complex trauma and other challenging conditions. She has conducted ACT trainings and workshops worldwide since 2001 and is the author of acclaimed books on ACT for professionals and general readers. Dr. Westrup has served as Director of both the Women's Mental Health Center and the Women's Trauma Recovery Program at the VA Palo Alto Health Care System.