Published in two volumes, the first in 1605 and the second in 1615, the novel Don Quixote is a cornerstone of Spanish and Western literature. It regularly appears on the short list of the most influential works ever written.
This story follows a Spanish gentleman that has read so many chivalric romances that he begins to blur the lines of fiction and reality and loses his mind. He brandishes the name Don Quixote and sets of to revive chivalry, correct injustices and restore order to the world. He recruits the farmer Sancho Panza as his side-kick to join him on his quest.
Trivia Points: The full title of the book is The Ingenious Gentleman Don Quixote of La Mancha, in Spanish El ingenioso hidalgo don Quijote de la Mancha. The phrase "Tilting at windmills", used to describe a fool-hardy task or quest was inspired by this book (by Chapter VIII to be specific).