In this essay I consider the future of personality development in light of the past effects of Personality and Assessment on the field of personality in general and personality development in particular. The essay is organized around 1) the effect of Mischel's book on the foundational theories informing personality development; 2) definitions of personality traits; 3) an alternative model of personality traits, described as the sociogenomic model of personality traits, that can bridge the divide that still characterizes the field of personality development; 4) the application of the sociogenomic model of personality traits to issues of personality trait development, and 5) a "Newtonian" vision for the future of personality psychology.