This chapter aims to compare the approaches known as evolutionary psychology, behavioral ecology, and dual inheritance theory with respect to their key assumptions, explanatory goals, and realms of application. These distinct approaches to evolutionary analysis of human behavior have each crystallized during the twenty-plus years since N. Chagnon and William Irons organized the 1976 American Anthropological Association symposia commemorated here–symposia which coincided roughly with the publication of E. O. Wilson's Sociobiology and Dawkins's The Selfish Gene. If human behavior is guided by special-purpose cognitive algorithms that are genetically canalized and adapted to the environment of evolutionary adaptedness (EEA). For if the divergence from the EEA is a product of cultural change, then culture is inescapably important in explaining contemporary human behavior. More optimistic, perhaps, is the hope that the not-too-distant future may see a synthesis of all three styles into a robust and pluralistic discipline focused on the evolutionary study of human behavior.