As rigorous scientific and philosophical discourse circulated during the Enlightenment, aided by the Republic of Letters, a revolutionary understanding of gender emerged that would impact nation building in Europe and the Americas. In From Virile to Sterile, Adriana Novoa analyzes the cosmopolitan citizens of this metaphysical republic—an international community of scholars and literary figures—and the first universal modern male identity it established. By the end of the eighteenth century, she reveals, men’s role in society had fundamentally changed. This "man of letters" possessed a masculinity that was learned and shareddifferent from the warrior model of the past. The modern man represented a new notion of patriotism linked to knowledge and institutions that promoted intellectual dynamism, change, and self-transformation. For a conservativism that despised radical liberalism and its science, this new masculinity was degenerate and villainous, a sign of extinction and sterility. The virile man was stable and unchanging, his authority rooted in continuity and stability. Novoa explores this complex gendering of science, modernity, and civilization in Argentina during the eighteenth and nineteenth centuries, and how a universal characterization of masculinity shaped the politics of the River Plate Viceroyalty and later the creation of the Argentine Republic.