The P of the Lewinian equation B=f(P,E) is addressed by a conceptual map of perspectives to characterize the P (persons). Most of these perspectives operate within personality psychology, so those perspectives are emphasized within personality; because several perspectives on the person operate within social psychology, those perspectives also are described. Lewin intended that the P and E (environment) parts of the equation be considered in tandem. Thus, this chapter considers from a personality perspective the integration between personality and social psychology; it argues that although integration has advanced, the two fields hold each other at an arm’s-length mutual acceptance. Last described are theories of personality, especially whole trait theory, that include both P and E as example ways to close that last arm’s-length distance. Whole trait theory traits are both explanatory and descriptive concepts, require both persons and situations to be described, and become investigated with both correlational and experimental methods.