Os Sertões (translated as Rebellion in the Backlands) (1902) is a book written by the Brazilian author Euclides da Cunha.

Mixing science and literature, the author narrates the story of a war that happened in the end of the 19th century, in Canudos, a settlement of Bahia's Sertão ("backland"), an extremely arid region where, even now, struggles against poverty, drought and political corruption continue.

During the war (1893–1897) against the republican army, the sertanejos (inhabitants of the backlands) were commanded by a messianic leader called António Conselheiro.

Source: http://en.wikipedia.org/wiki/Os_Sert%C3%B5es

In 1981, a version of the story was rewritten by Peruvian novelist Mario Vargas Llosa as "The War of the End of the World" (= "La guerra del fin del mundo") Vargas Llosa also dedicates his novel to Euclides da Cunha.