The novel is narrated by the dead protagonist, Brás Cubas, who tells his own life story from beyond the grave, noting his mistakes and failed romances.

The fact that he is already deceased allows Brás Cubas to sharply criticize Brazilian society and reflect on his own disillusionment, with no sign of remorse or fear of retaliation.

Brás Cubas dedicates his book: "To the worm who first gnawed on the cold flesh of my corpse, I dedicate with fond remembrance these Posthumous Memoirs" (Portuguese: Ao verme que primeiro roeu as frias carnes do meu cadáver dedico com saudosa lembrança estas Memórias Póstumas), which indicates that not a single person he met through his life deserved the book.

[1] The author explains the style of the book before beginning the story with his funeral and cause of death - "Brás Cubas poultice", a medical panacea that was his last obsession and "would guarantee him glory among men".

At the age of seventeen, Brás Cubas falls in love with a prostitute named Marcela, an affair which lasts "fifteen months and eleven contos" and almost wipes out the family fortune.

After a few years of wild bohemianism, "following romanticism in practice and liberalism in theory," he returns to Rio de Janeiro on the occasion of the death of his mother.

He falls in love with a girl named Eugênia, the daughter of Dona Eusébia, a poor friend of the family, who turns out to be lame from birth.

With the death of Brás Cubas' father, conflict breaks out over the inheritance between him and his sister Sabina, and her husband Cotrim.

To keep the affair secret Brás Cubas bribes Virgília's former seamstress Dona Plácida to act as the resident of a small house in Gamboa, which serves as a meeting place for the lovers.

Lobo Neves is appointed governor of a province and leaves with Virgília for the north, ending the affair.

Ironically, while going out to take care of his project, he is caught in a rainstorm and catches pneumonia, from which he dies at age sixty-four.

It is important to note that Assis created a philosophical theory to criticize Positivism, which was common in Brazil's literature back then.

The theory in question was Humanitism, created in the books by Quincas Borba, a friend of Brás Cubas who had gone mad before dying.

Assis, through an ingenious fallacy, implied that envy is positive, in the same way many theories could "prove" true something clearly absurd looking through today's eyes.

[6] In 2020, there were two new translations, by Flora Thomson-DeVeaux (Penguin Classics) and Margaret Jull Costa and Robin Patterson (Liveright).