Over the past few years there has been an increased interest in the identification and treatment of substance use disorders, due at least in part to the widespread drug overdose epidemic. Clinicians and the lay public have gained a greater understanding of the need for treatment of substance use disorders and the consequences of avoiding treatment. In addition, there has been a growing understanding of substance use disorders as medical or mental health disorders, rather than as character flaws or merely illegal activities. This book builds on this nascent understanding and presents epidemiology, basic science, and treatment from the perspective of a clinician who wants to gain the knowledge and background needed to work with this patient population. The overall theme of the book is to discuss evidence-based rather than anecdotal or unproved treatments. Section I begins with the epidemiology, etiology, and neurobiology of substance use disorders, including preclinical data. Section II discusses pharmacotherapy for substance use disorders, focusing on medications approved by the US Food and Drug Administration (FDA). Section III focuses on other evidence-based treatments for substance use disorders, including behavioral therapies, and ends with potential future treatments.