Eric J. Mash, PhD, is Professor of Psychology in the Department of Psychology and Program in Clinical Psychology at the University of Calgary. He has served as an editor, editorial board member, and editorial consultant for many scientific and professional journals; and has published numerous books and journal articles. Russell A. Barkley, PhD, ABPP, ABCN, is Clinical Professor of Psychiatry and Pediatrics at the Medical University of South Carolina. Dr. Barkley has published numerous books and five assessment scales, plus more than 260 scientific articles and book chapters on ADHD, executive functioning, and childhood defiance. He is also the editor of the newsletter The ADHD Report. A frequent conference presenter and speaker who is widely cited in the national media, he is past president of the Section on Clinical Child Psychology (the former Division 12) of the American Psychological Association, and of the International Society for Research in Child and Adolescent Psychopathology. His website is www.russellbarkley.org.