The Spanish novel enjoyed unparalleled success in the seventeenth century, either independently or as a short piece gathered in a collection. Although it frequently dealt with different variations of love, honor, leisure, and friendship, it also explored unspeakable acts like incest, rape, pederasty, and even bestiality. Scholars working on the novel’s trajectory from an Italianate experiment (Miguel de Cervantes) to an allegorized portrayal of city life (Francisco Santos) have shied away from examining these transgressive themes. Incest, in particular, presents a fascinating paradox: its treatment in contemporary theater, usually drawn from myth and folklore, has been widely studied, whereas its narrative presence, freed from tradition and more attuned to the time, remains largely unexplored. Drawing on historical parameters like the decrees on incest by the Council of Trent as well as on recent debates active in the social sciences and literary studies, this lecture examines a selection of short stories published at different moments of the century that delved into this taboo. Rather than a form of Baroque excess, the narrative construction of incest should be examined as a fertile tactic through which the novel engaged with national history, societal expectations, civil and canon law, and the (ever increasing) institutional control over the genre.