Abstract: For most of this past century, scholarship on the topics of personality and emotion has emerged from the humanities and social sciences. In the past decade, a remarkable change has occurred in the influence of neuroscience on the conceptualization and study of these phenomena. This article argues that the categories that have emerged from psychiatric nosology and descriptive personality theory may be inadequate, and that new categories and dimensions derived from neuroscience research may produce a more tractable parsing of this complex domain. The article concludes by noting that the discovery of these biological differences among individuals does not imply that the origins of these differences lie in heritable influences. Experiential shaping of the brain circuitry underlying emotion is powerful. The neural architecture provides the final common pathway through which culture, social factors, and genetics all operate together.