In literature, film, and other such arts, an unreliable narrator is a narrator who cannot be trusted, one whose credibility is compromised. They can be found in fiction and film, and range from children to mature characters. While unreliable narrators are almost by definition first-person narrators, arguments have been made for the existence of unreliable second- and third-person narrators, especially within the context of film and television, but sometimes also in literature.
Illustration by Gustave Doré of Baron Munchausen's tale of being swallowed by a whale. Tall tales, such as those of the Baron, often feature unreliable narrators.
A frame story is a literary technique that serves as a companion piece to a story within a story, where an introductory or main narrative sets the stage either for a more emphasized second narrative or for a set of shorter stories. The frame story leads readers from a first story into one or more other stories within it. The frame story may also be used to inform readers about aspects of the secondary narrative(s) that may otherwise be hard to understand. This should not be confused with narrative structure. A notable example is The Decameron.
One of the earliest frame stories is in the Odyssey, which begins with Odysseus telling stories to King Alcinous on the island of Scheria. Painting of Odysseus at the Court of Alcinous by Francesco Hayez, 1814-1815
One Thousand and One Nights frames many stories with a single narrator, Shahrazad; embedded within it are further framed sets of tales, such as those of Sindbad the Sailor. Illustration Sindbad the sailor and Ali Baba and the forty thieves by William Strang, 1896
The Return of Rip Van Winkle, painting by John Quidor, 1849