This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book provides an updated, practical description of present science-based understanding of attention deficit hyperactivity disorder (ADHD) as a syndrome of developmental impairments in the brain’s self-management system, its executive functions. It explains the syndrome previously known as Asperger Syndrome, now eliminated from the diagnostic manual. The book then describes four successful adults who suffered from social-emotional impairments which were not recognized until they were in their middle adult years. It also provides rich details about a variety of particular children, teens and adults seen and diagnosed in the clinic who are quite smart while they also suffered from social-emotional impairments clinicians describe as Asperger syndrome in addition to their having ADHD. The book illustrates how both Asperger syndrome and ADHD are often accompanied by some or many features of learning problems, emotional syndromes or behavioral difficulties.