As legislation continues to evolve and the stigma surrounding addiction persists, new findings on the impact of substances on the brain are an important public issue. This second edition integrates major developments in human and animal neuroscience to explain how addictive substances and behaviors reshape brain circuits governing reward, stress, habit formation, and self-control. New and enhanced coverage addresses individual differences-including age, sex, stress, pain, comorbidity, and emerging substances-as well as advances in neuroimaging, genetics, and treatment science. Students are supported by learning objectives, real-world examples and applications, review questions, and further reading lists, equipping them with the conceptual tools needed to understand vulnerability, persistence, relapse, and recovery in addiction. Instructors have access to supplementary resources, including lecture slides, review questions and answers, and a test bank.