Three leading drug policy scholars provide a comprehensive introduction to the field, covering everything from the pharmacology of major substances to the effectiveness of various policy interventions. Mark Kleiman, Jonathan Caulkins, and Angela Hawken examine drug use patterns, the harms associated with different substances, the impacts of prohibition versus legalization, and innovative approaches like drug courts and treatment programs. Their framework emphasizes harm reduction while acknowledging that all policy choices involve tradeoffs. The book covers alcohol, tobacco, marijuana, and harder drugs, recognizing that different substances present different challenges requiring different responses. The authors' approach is analytical rather than ideological, evaluating policies based on evidence of what actually reduces harm rather than on moral or political preferences. They examine how prohibition creates black markets and mass incarceration while also acknowledging that legal availability increases use. Their treatment of marijuana legalization has been particularly influential, as several of their predictions about commercial legalization's effects have proven accurate. For anyone seeking to understand drug policy beyond slogans - whether policymakers, students, or citizens - this work provides essential grounding in what we know about drugs and what works to reduce their harms.