Russell A. Barkley, PhD, ABPP, is Clinical Professor of Psychiatry at the Medical University of South Carolina and Research Professor of Psychiatry at the State University of New York Upstate Medical University in Syracuse. He was previously Director of Psychology and Professor of Psychiatry and Neurology at the University of Massachusetts Medical School. Dr. Barkley has published extensively on ADHD and has received numerous awards for his scientific and clinical contributions. He served as the principal investigator on the two large research projects reported in this volume. nbsp; Kevin R. Murphy, PhD, is founder and Director of the Adult ADHD Clinic of Central Massachusetts in Northborough. He was previously Director of the Adult ADHD Clinic and an Associate Professor of Psychiatry at the University of Massachusetts Medical School. He has published extensively on adults with ADHD and consults widely on the clinical diagnosis and management of ADHD in adults. Dr. Murphy served as the coinvestigator on the research study of clinic-referred adults with ADHD reported in this volume and conducted the clinical evaluations of all of the adults in that project. nbsp; Mariellen Fischer, PhD, is a pediatric neuropsychologist and Professor in the Division of Neuropsychology, Department of Neurology, Medical College of Wisconsin. Dr. Fischer has published numerous articles on ADHD, developmental psychopathology, and neuropsychology. She and Dr. Barkley have reported the earlier results of the Milwaukee longitudinal study of hyperactive children, the adult outcome of which is presented in this book. Dr. Fischer served as coinvestigator and the Milwaukee site principal investigator on the longitudinal study reported in this volume.