O Guarany is set back in 1604, a period when Portugal and its colonies submitted to Spanish dominion due to a lack of heirs to ascend to the throne. Alencar takes advantage of this dynastic complication to resurrect the historical figure of D. Antônio de Mariz, a nobleman connected to the foundation of the city of Rio de Janeiro and a pioneer settler. This historical (factual) background, which orients the novel throughout, is set in the first two chapters; then fantasy, both violent and erotic, starts to prevail.
The novel is still widely read nowadays, especially at Brazilian schools as an introduction to novel reading, but also by anyone who enjoys a thrilling adventure story. Literary criticism has tended to link O Guarani to the works of Fenimore Cooper, Chateaubriand and the noble savage from the Rousseauesque tradition. However, this interpretation of the novel has become outdated as recent academic works show also how dark, sexual, gothic and lyrical (over narrative, unlike the Fenimore Cooper model) the novel is.
The Guarani is the Brazilian novel with the largest number of adaptation for comics.