The epigraph serves to link the work to a wider literary canon. The long quotation from Dante's Inferno that prefaces T. S. Eliot's 'Love Song of J. Alfred Prufrock' is part of a speech by one of the damned souls in Dante's Hell. Linking it to the monologue which forms Eliot's poem adds a comment and a dimension to Prufrock's confession. The epigraphs to the Preamble of Georges Perec's La Vie mode d'emploi (Life: A User's Manual) and to the book as a whole warn the reader that tricks are going to be played and that all will not be what it seems.
Some authors use fictional quotations that purport to be related to the fiction of the work itself. For example, Stephen King's Misery has epigraphs taken from the fictitious novels written by the protagonist; Jasper Fforde's The Eyre Affair has quotations from supposedly future works about the action of the story. Some science fiction authors (Isaac Asimov's Foundation Trilogy is an example) are fond of using quotations from an imagined future history of the period of their story. This can be seen as a way of claiming authenticity for a work of the imagination.