Twentieth-century Catholic theology was strongly affected by Henri de Lubac’s claim that the western theological tradition went awry by allowing that one could have an adequate idea of human nature without reference to humanity’s supernatural end. According to de Lubac, the culprits were early modern scholastics, and their mistake was the idea of pure nature. Aquinas’s Notion of Pure Nature and the Christian Integralism of Henri de Lubac: Not Everything Is Grace contributes to the current literature criticizing de Lubac’s thesis. Specifically, it offers an explanation for its enduring power and popularity with particular attention to the contemporary Radical Orthodoxy movement.