"O Cortiço" by Aluísio Azevedo is a naturalist novel published in 1890. Set in a Rio de Janeiro tenement at the end of the nineteenth century, the work exposes exploitation and harsh living conditions under unchecked capitalism. The story follows Portuguese merchant João Romão's ruthless climb up the social ladder while chronicling the struggles of the tenement's diverse inhabitants. Their intertwined fates reveal how environment and instinct shape human behavior, as characters abandon families, pursue forbidden passions, and fight for survival in a world governed by the strongest.