To build a science of the person, the most basic question was, and remains, how can one identify and understand the psychological invariance that distinctively characterizes an individual and that underlies the variations in the thoughts, feelings, and actions that occur across contexts and over time? This question proved particularly difficult because of the discrepancies that soon emerged between the expressions of consistency that were expected and those that were found. The resulting dilemma became known as the classic "personality paradox": How can we reconcile our intuitions-and theories-about the invariance and stability of personality with the equally compelling empirical evidence for the variability of the person's behavior across diverse situations? Which is right: the intuitions or the research findings? In this chapter I review and discuss some of the advances made to answer this question since it was posed. These findings have allowed a resolution of the paradox, and provide the outlines for a conception of the underlying structure and dynamics of personality that seems to better account for the data.