Book excerpt: For many years, addiction research focused almost exclusively on men. Yet scientific awareness of sex and gender differences in substance use disorders has grown tremendously in recent decades. This volume brings together leading authorities to review the state of the science and identify key directions for research and clinical practice. Concise, focused chapters illuminate how biological and psychosocial factors influence the etiology and epidemiology of substance use disorders in women; their clinical presentation, course, and psychiatric comorbidities; treatment access; and treatment effectiveness. Prevalent substances of abuse are examined, as are issues facing special populations.