"Os Sertões", written by Euclides da Cunha and published in 1902, is a fundamental work of Brazilian literature that combines elements of sociology, history, and literature. The book is divided into three parts: "The Land," "The Man," and "The Struggle."

In the first part, "The Land," Euclides da Cunha describes the geography and climatic conditions of the northeastern sertão of Brazil, highlighting the region's aridity and its natural characteristics. He analyzes how these factors influence the lives of its inhabitants and the formation of local culture.

In "The Man," the author explores the psychology and characteristics of the sertanejos, especially the jagunços, who are the protagonists of the story. He addresses the relationship between culture, religion, and the struggle for survival in a hostile environment, emphasizing the social formation and traditions of the northeastern people.

The third part, "The Struggle," narrates the War of Canudos, an armed conflict that took place between 1896 and 1897, in which the Brazilian government fought against the followers of Antonio Conselheiro, a charismatic leader who attracted the marginalized of society. This section describes the events leading to the siege and destruction of Canudos, highlighting the violence and injustices faced by its inhabitants.

"Os Sertões" is a profound analysis of Brazilian reality, particularly the social and cultural tensions between the sertão and urban areas, and it offers a vivid portrait of the struggle for survival and the resilience of the northeastern people. The work is recognized not only for its sociological content but also for its poetic prose and striking literary style, solidifying Euclides da Cunha as one of the great authors of Brazilian literature.