Matthieu Villatte, PhD, is Research Scientist and Clinical Trainer at the Evidence-Based Practice Institute in Seattle. He has conducted workshops on the clinical applications of RFT and contextual behavioral science in the United States, Canada, Australia, and Europe. He is also an associate editor of the Journal of Contextual Behavioral Science. Dr. Villatte's current work focuses on the dissemination of evidence-based practices, and he has published articles and book chapters on RFT, contextual behavioral science, and cognitive-behavioral therapy. Jennifer L. Villatte, PhD, is a clinical psychologist committed to advancing health equity through contextual behavioral science. She is Assistant Professor of Psychiatry and Behavioral Sciences at the University of Washington, where she partners with innovators in computer engineering, human-centered design, and data science to maximize the effectiveness and reach of behavioral interventions that enhance individual and community well-being. Steven C. Hayes, PhD, is Foundation Professor of Psychology Emeritus at the University of Nevada and a codeveloper of acceptance and commitment therapy. His career has focused on the analysis of the nature of human language and cognition and its application to the understanding and alleviation of human suffering. He has served as president of multiple scientific and professional organizations, including the Association for Behavioral and Cognitive Therapies (ABCT) and the Association for Contextual Behavioral Science. His work has been recognized by the Award for Impact of Science on Application from the Society for the Advancement of Behavior Analysis and the Lifetime Achievement Award from the ABCT, among other awards. The author of 41 books and over 575 scientific articles, Dr. Hayes has focused on understanding human language and cognition and applying this understanding to the alleviation of human suffering and the promotion of human welfare. He is coauthor of Acceptance and Commitment Therapy, Second Edition.