From the core behavioral dimensions of attention and impulse control, to the clinical manifestations of ADHD and disruptive behavior disorders, both voluminous science and major societal controversy exist. I review my lab's longstanding program of research on core cognitive mechanisms, risk and etiologic factors, the roles of parenting and peer relations in the unfolding of symptoms and impairments, sex differences (including heterotypically continuous trajectories of girls with ADHD that involve major risk for self-harm), and the role of educational policy in fueling major increases and state-by-state variation in diagnostic prevalence.