The five-factor model has recently received wide attention as a comprehensive model of personality traits. The claim that these five factors represent basic dimensions of personality is basad on four lines of reasoning and evidence: (a) longitudinal and cross-observer studies demonstrate that all five factors are enduring dispositions that are manifest in patterns of behavior; (b) traits related to each of the factors are found in a variety of personality systems and in the natural language of trait description; (c) the factors are found in different age, sex, race, and language groups, although they may be somewhat differently expressed in different cultures; and (d) evidence of heritability suggests that all have some biological basis. To clarify some remaining confusions about the five-factor model, the relation between Openness and psychometric intelligence is described, and problems in factor rotation are discussed.