This document provides an overview of key concepts from the first chapter of the textbook Drugs and Society. It defines what constitutes a drug and psychoactive drugs. It also outlines the major types of commonly abused drugs and discusses factors that affect drug use like biological, cultural, social, and contextual factors. Statistics on drug use in the United States are presented on alcohol, tobacco, marijuana, and other drugs. Characteristics of experimental, compulsive, and casual drug users are defined. The stages of drug dependence and criteria for substance use disorder are outlined.