This thesis traces the production and critical reception of science fiction in Brazil from the mid-nineteenth century to the early twenty-first century. It investigates the long process of the genre’s marginalisation within the national literary field, arguing that this exclusion is inseparable from the ways Brazilian literary canons have been constructed. Those canons have historically been organised around two complementary poles: a “high” or erudite tradition that legitimates national intellectuals through alignment with European high culture, and a “popular” tradition, also mediated by the same elite, that ideologically affirms myths of Brazilian identity. By analysing critical discourse on science fiction alongside the material conditions of its production and circulation, the study shows how the genre has been repeatedly marked as foreign, mass-cultural, and therefore illegitimate. The thesis situates this history within four intersecting contemporary debates: Latin American and peripheral science-fiction studies; world literature and the political economy of form; postcolonial and decolonial approaches to genre (including the Brazilian reinvention of anthropophagy); and cultural precarity on the periphery. In doing so, it offers both an archive-based account of Brazilian science fiction and a critical vocabulary for understanding why a literature of the future has so often been denied a future within the national literary field. Original Portuguese Master’s thesis defended at PUC-Rio in 2005. English translation by the author completed in 2026. The historical research, corpus, and critical claims remain those of the original work. Some passages were clarified for an international readership.