The pamphlet "What is Addiction" explains addiction as a chronic, relapsing brain disease characterized by compulsive drug seeking and use, despite harmful consequences. It highlights the dangers of different drug categories, including sedatives, stimulants, and hallucinogens, and their potential health and behavioral impacts. The document emphasizes the importance of combined medication and behavioral therapy in the treatment process, including detoxification, ongoing therapy, and relapse prevention. Additionally, it provides contact information for addiction treatment resources.