The psychologist Timothy Leary (1920–1996), an iconic cultural figure in the United States in the 1960s and afterward, has received comparatively scant attention in the history of psychology. This may be due to perceptions that, after a major career shift centering around his experimentation with psychedelic substances and his subsequent dismissal from Harvard in 1963, Leary parted company with the field. While there are several good reasons to adopt this view, examination of his entire career as well as his intellectual ancestry reveals unacknowledged continuities, suggesting that a more prominent place be accorded to him in the history of psychology, as well as to the challenges he poses.