Steven C. Hayes, PhD, is Nevada Foundation Professor and director of clinical training in the department of psychology at the University of Nevada. An author of forty-one books and nearly 600 scientific articles, his career has focused on analysis of the nature of human language and cognition, and its application to the understanding and alleviation of human suffering and promotion of human prosperity. Among other associations, Hayes has been president of the Association for Behavioral and Cognitive Therapies, and the Association for Contextual Behavioral Science. His work has received several awards, including the Impact of Science on Application Award from the Society for the Advancement of Behavior Analysis, and the Lifetime Achievement Award from the Association for Behavioral and Cognitive Therapies.