The interpolated novellas are stories with their own subject matter that Part One places within the inn, without the gentleman as protagonist. The two best known are that of The Curious Impertinent, read aloud by the priest, and that of the captive and Zoraida, told by the captive himself; around them the book inserts smaller stories that belong to others, such as that of Marcela and Grisóstomo, that of Cardenio and Dorothea, and that of Leandra.
The Curious Impertinent occupies chapters XXXIII to XXXV: Anselmo asks his best friend, Lothario, to test the virtue of Camilla, his wife; Camilla gives in; the novella ends with the deaths of all three. The captive's tale runs from chapters XXXIX to XLI: the father who divided his estate among three sons and three roads, Lepanto, captivity in Algiers, Zoraida's letter, and the escape by boat to Spain. A magistrate who arrives at the inn is the captive's brother.
The book discusses its own device. The priest says of The Curious Impertinent that the novella seems good to him, but that he cannot persuade himself it is true, and that if it is made up, the author made it up badly, since one cannot imagine a husband so foolish as to want to undertake such a costly test. In Part Two, the bachelor Sansón Carrasco disapproves of the novella, because it is not from that place nor related to the story of Don Quixote, and in chapter XLIV the narrator explains that this time he preferred episodes born of the same events, not loose novellas.
That is why the novellas are the other half of the book's idea: in the middle of a story about someone who takes fiction for truth, they are fictions that the listeners find well written and implausible. Whoever reads them discovers that the book does not treat fiction in only one way.