Don Quixote by Miguel de Cervantes

Don Quixote is a novel written by Miguel de Cervantes, fully titled The Ingenious Gentleman Don Quixote of La Mancha. The novel Don Quixote ("best literary work ever written") follows the adventures of Alonso Quijano, who reads too many chivalric novels, and sets out to revive chivalry under the name of Don Quixote. He recruits a simple farmer, Sancho Panza, as his squire, who frequently deals with Don Quixote's rhetorical orations on antiquated knighthood with a unique Earthy wit.
The protagonist of the novel Don Quixote, is a gentleman nearing fifty years of age, living in La Mancha. While mostly a rational man of sound reason, his reading of books of chivalry in excess has had a profound effect on him, leading to the distortion of his perception and the wavering of his mental faculties. In essence, he believes every word of these books of chivalry to be true though, for the most part, the content of these books is clearly fiction. Otherwise, his wits, in regards to everything other than chivalry, are intact. He decides to go out as a knight-errant in search of adventure. He dons an old suit of armour, renames himself "Don Quixote de la Mancha," and names his skinny horse "Rocinante". Don Quixote designates a neighboring farm girl as his lady love, renaming her Dulcinea del Toboso, while she knows nothing about this. Don Quixote de la Mancha sets out in the early morning and ends up at an inn, which he believes to be a castle. He asks the innkeeper, whom he thinks to be the lord of the castle, to dub him a knight ... and all adventures begin... (Summary by Wikipedia)