Timothy J. Trull, Ph.D., is professor of psychological sciences at the University of Missouri. Dr. Trull received his Ph.D. from the University of Kentucky and completed his internship at New York Hospital Cornell Medical Center. His research interests are in the areas of diagnosis and classification of mental disorders; borderline personality disorder; substance use disorders; clinical assessment; professional issues in clinical psychology; and ambulatory assessment methods. Dr. Trull has received several awards and honors for his teaching and mentoring, including Psi Chi Professor of the Year, the Robert S. Daniels Junior Faculty Teaching Award, and most recently the MU Graduate Faculty Mentor Award. He enjoys teaching Abnormal Psychology and Introduction to Clinical Psychology; his textbook, CLINICAL PSYCHOLOGY, is used in classes across the U.S. and internationally. A licensed psychologist, Dr. Trull continues to train future clinical psychologists in the assessment, prevention, and treatment of psychological disorders.