Overview chapter.- Imaging studies linking dopaminergic systems to impulsivity in humans.- The Genetics of Externalizing Problems.- The neuropharmacology of impulsive behaviour: ten years later.- Inhibitory control and impulsivity in childhood onset disruptive behavior disorders.- Steep discounting of future rewards as an impulsivity phenotype: a concise review.- Developmental considerations in impulsivity: Implications for research and treatment.- Reinforcer Pathology: Implications for Substance Abuse Intervention.- Impulsivity and Suicidal Behavior.- Sex differences in neural circuits underlying inhibitory control.- The role of impulsivity facets on the incidence and development of alcohol use disorders.- The neurobiology of reinforcement learning mechanisms in impulsivity.