Stefan G. Hofmann, PhD, is professor of psychology in the department of psychological and brain sciences at Boston University. He has been president of numerous professional organizations, and is currently editor in chief of Cognitive Therapy and Research. He has published more than 400 peer-reviewed journal articles and twenty books. He is a highly cited researcher, and has received many awards, including the Humboldt Research Award. His research focuses on the mechanism of treatment change, translating discoveries from neuroscience into clinical applications, emotion regulation, and cultural expressions of psychopathology. He is codeveloper (with Steven C. Hayes) of process-based therapy.Robert L. Leahy, PhD, is author or editor of twenty-seven books, including The Worry Cure, The Jealousy Cure, and Beat the Blues. He is director of the American Institute for Cognitive Therapy in New York, NY, and clinical professor of psychology at Weill Cornell Medical College. Leahy has been featured in The New York Times, The Wall Street Journal, and more.