Pediatrician Lawrence Diller specializes in child development and behavior. He's evaluated hundreds of patients for attention deficit disorder, for which the drug Ritalin has often been prescribed. His new book "Running on Ritalin: A Physician Reflects on Children, Society, and Performance in a Pill." (Bantam Books). After seeing more and more parents come into his practice asking for Ritalin for their children, Diller became concerned, and wrote an article in 1996 that started a national debate about the use of the drug.