This chapter is a personal synthesis of the past five decades of research efforts to understand cultural influences on individual social-personality processes and outcomes. The author identifies four developmental stages in refining our conceptualization of how culture impacts upon individual functioning and discusses problems associated with each stage: in the Eureka Stage, cross-cultural researchers documented average differences between samples from two or occasionally more cultural groups and speculated about reasons for these differences. In the Mercator Stage, psychological measures taken from many cultural groups were averaged then factor analyzed to provide culture-level mappings of groups. In the Psychological Unpackaging Stage, cultural differences in psychological measures were shown to be associated with personality differences distinguishing the cultural groups. In the Cross-Level Stage, sufficient numbers of cultural groups have been assessed to enable empirical evidence to indicate what features of the cultures involved might influence the psychological processes and outcomes examined. Increasingly, individuals are treated as polycultural, introducing further complexity into research on culture’s influence.