Dr. Russell Barkley is a clinical psychologist and one of the world's foremost experts on attention-deficit hyperactivity disorder (ADHD). He recently retired as the clinical professor of psychiatry at the VCU Medical Center. He's an author of many books on ADHD, including his latest best-seller, "12 Principles for Raising a Child with ADHD". Dr. Barkley has been Involved in research since 1973 and a licensed psychologist since 1977. He has devoted much of his scientific career to studying ADHD and related fields.