Os Sertões (translated as Rebellion in the Backlands) (1902) is a book written by the Brazilian author Euclides da Cunha, widely considered one of the greatest achievements of Brazilian and even World literature. 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 Antonio Conselheiro.
Euclides da Cunha (January 20, 1866 – August 15, 1909) was a Brazilian writer, sociologist and engineer. His most important work is Os Sertões (Rebellion in the Backlands), a non-fictional account of the military expeditions promoted by the Brazilian government against the rebellious village of Canudos, known as the War of Canudos. This book was a favorite of Robert Lowell, who put it above Tolstoy, the Russian writer. Jorge Luis Borges also commented on it in his short story "Three Versions of Judas".