Substantive progress has been made in our understanding of children considered hyperactive, especially in the interpersonal sphere. Evolving conceptualizations of hyperactivity and attention deficits are reviewed briefly, including changes in clinical diagnostic practices and in knowledge about developmental course. The hypothesis is advanced that the cognitive and social difficulties of hyperactive children may be better understood in terms of motivational and self-regulatory processes than as deficiencies in basic information processing. The role of stimulant medication is emphasized, both as a controversial treatment approach and as an adjunct to research on the children's problems.