1. Introduction2. History and Prevalence of ADHD in Adults3. Diagnostic Criteria for ADHD in Adults4. Defining ADHD in Adults: Making the Diagnosis in the UMASS and Milwaukee Studies5. DSM Symptom Utility and the Issue of Age of Onset6. Impairment in Major Life Activities7. Identifying New Symptoms of ADHD in Adulthood 8. Comorbid Psychiatric Disorders and Psychological Maladjustment9. Educational and Occupational Functioning10. Drug Use and Antisocial Behavior11. Health, Lifestyle, Money Management, and Driving12. Sex, Dating and Marriage, Parenting, and Psychological Adjustment of Offspring13. Neuropsychological Functioning14. Summary, Conclusions, and Treatment Implications