In her book of short stories Ciudad Real (1960) and her novels Balun-Canan (1957) and Oficio de tinieblas (1962), Rosario Castellanos interprets the collective and individual problems of the ethnic groups that inhabit the Mexican State of Chiapas: both the Indians and the whites. Each of the groups insists on the perpetuation of archaic values, a fact that keeps them in an ahistorical and lethargic dimension. Castellanos uses as her point of reference the world-vision of both social nuclei to delve into the psychology of her literary characters Throughout her short stories and novels, the author recreates the same themes and surroundings and creates characters whose individual problems have their origin in their cultural values. Nevertheless, the analysis of Ciudad Real, Balun-Canan and Oficio de tinieblas shows that the writer does develop artistically in the material she chooses for shaping her fictitious universe. That is why before developing the proposed theme of this dissertation, a critical evaluation of the earlier works, Balun-Canan and Ciudad Real was necessary In the second and third chapters of the dissertation there is a separate discussion of the Indians' and the whites' conception of the world and of how their scale of values leads to the existential anguish of the characters In the last part of the dissertation there is an analysis of the linguistic resources, the narrative techniques, and the structure of Oficio de tinieblas. This analysis is used to demonstrate that the narrative resources used by the author are to give form to her novelistic world which are intimately fused to or correspond with the conflicts present in the plot