In the Prologue, Cervantes uses an extended metaphor that describes the novel as his own stepchild:
It can happen that a man has an ugly, charmless son, and his love blindfolds him to prevent him from seeing the child’s defects: on the contrary, he regards them as gifts and graces, and describes them to his friends as examples of wit and cleverness. But although I seem like Don Quixote’s father, I am his stepfather, and I don’t want to drift with the current of custom, or beg you [..] to forgive or excuse the defects that you see in this my son; and you are neither his relative nor his friend [...]
Here, Cervantes metaphorically characterizes the novel, with wry humor, as “an ugly, charmless son” and insists that he is not blind to the “child’s defects.” While some fathers, he notes, might regard those defects as “gifts and graces” and make excuses for their child, Cervantes regards himself, instead, as a “stepfather” who does not have so much loyalty to his child. Through this metaphor, Cervantes suggests that he does not intend to defend his novel nor deny its weaknesses, and further, he implores the reader to criticize the novel when warranted. Throughout the Prologue, he presents the novel with both humility and humor.
The narrator uses a series of metaphors when describing Don Quixote’s desire to “find a lady of whom he could be enamoured”:
[He] realized that the only remaining task was to find a lady of whom he could be enamoured; for a knight errant without a lady-love is a tree without leaves or fruit, a body without a soul. He said to himself: ‘If, for my wicked sins or my good fortune, I encounter some giant, as knights errant usually do, and I dash him down in single combat, or cleave him asunder, or, in short, defeat and vanquish him, will it not be proper to have someone to whom I can send him as a tribute.'
Don Quixote has already prepared his suit of armor and readied his horse in order to assume his new role as a knight errant. Now, he feels that the only remaining task is to find a female paramour to whom he can dedicate his various achievements as he seeks adventure across Spain. “A knight errant without a lady-love,” the narrator states, “is a tree without leaves or fruit, or a body without a soul.” Here, the narrator uses two different metaphors that suggest that a knight would be incomplete without a lover. Hoping to fulfill this chivalric convention, Don Quixote decides to pick a local woman named Aldonza Lorenzo as his paramour, and though she does not appear directly in the novel, he references her repeatedly as “Dulcinea del Toboso” throughout his adventures. Dulcinea serves as a major source of motivation and inspiration for Don Quixote despite being an "unseen" character who is presumably unaware of his affections.
After Don Quixote, injured and exhausted, returns from his first attempt to seek adventure, his family and loved ones gather together in his home to care for him and find a solution to his apparent “madness.” After agreeing that his books have had a negative effect on his mental health, they decide to burn them. Don Quixote’s niece uses a simile that compares the books to “heretics” and the priest, following from her rhetoric, uses a series of metaphors drawn from religion and law:
‘I’m the one to blame for it all, not telling you gentlemen about my uncle’s madness so you could have done something about it and burned those unchristian books of his before it came to all this; he’s got lots and lots of them, and they do deserve to be put to the flames, like heretics.’
‘I agree with that,’ said the priest, ‘and I swear that before another day has passed they’ll be put on public trial and condemned to the flames so that they can’t make anyone reading them do what my friend must have done.’
Don Quixote’s niece describes the “unchristian books,” in a simile, as being “like heretics” insofar as she believes they should be burned at the stake, a typical punishment for religious heresy in early modern Europe. The priest, who agrees that the books should be burned, metaphorically suggests that they should be put on “public trial and condemned to the flames,” again invoking both the law and religion and figuring the burning of the books as a sort of legal punishment. Later, they sort through Don Quixote’s library to find those books they regard as responsible for his erratic behavior.
After the priest recommends that they spare Don Quixote’s poetry books, noting that they are far more intellectual and therefore less damaging than his books of chivalric literature, Don Quixote’s niece uses a metaphor that compares interest in poetry to an “incurable disease” in her argument to add the poetry books to the bonfire:
‘Oh sir,’ cried the niece, ‘please have them burned like the rest, because it could well happen that once my uncle gets over his chivalry illness he starts reading all these other books and takes it into his head to become a shepherd and wander about the forests and meadows singing and playing music and, what would be even worse than that, turn into a poet, which they say is a catching and incurable disease.’
‘The girl’s right,’ said the priest, ‘and it’ll be a good idea to remove this dangerous stumbling-block from our friend’s way.'
Though the primary target of Cervantes’s satire throughout Don Quixote is chivalric literature, he also occasionally satirizes other forms and genres of literature. Here, Don Quixote’s niece imagines that, once her uncle “gets over this chivalry illness,” he will begin to read poetry and attempt to “become a shepherd and wander about the forests and meadows singing and playing music.” She offers a mocking description of pastoral poetry, which often features rustic settings and shepherds. Further, she adds, he might become a poet himself, which she describes metaphorically as “a catching and incurable disease.” In this passage, then, Cervantes satirizes poetry and suggests that Don Quixote, as a result of his obsessive nature, might fixate upon some other form of literature after his tales of knights and heroes are burned.
Cervantes uses an extended metaphor and numerous allusions in a comic scene in which the members of Don Quixote’s household put the books of his library on trial, condemning many of them to the flames in order to weaken their influence on him. In one passage, they examine The Four Books of Amadis of Gaul after Don Quixote’s niece recommends burning all of the books without further examination:
The housekeeper said much the same, so anxious were both women to see those innocents massacred, but the priest wouldn’t agree without at least reading the titles. The first one that Master Nicolás put into his hands was The Four Books of Amadis of Gaul, and the priest said: ‘This is a strange coincidence: I’ve heard that this was the very first chivalry romance to be printed in Spain [...] so it seems to me that, as the prophet of such a pernicious sect, it should be condemned to the flames without delay.’
In this passage, Cervantes maintains an extended metaphor in which the books are under trial for religious heresy, describing the housekeeper and niece as zealots who wish to “see those innocents massacred.” The priest, in contrast, takes a more moderate approach, deciding to look at the books individually and recommending to spare some. First, they examine The Four Books of Amadis of Gaul, a favorite of Don Quixote and, as the priest explains, “the very first chivalry romance to be printed in Spain.” The priest, recognizing the important role that the Amadis of Gaul stories have played in spreading chivalric literature through Spain, declares the book, in a metaphor, as a “prophet” of a “pernicious sect” that should be “condemned to the flames” immediately. Through this allusion, Cervantes looks at the origins of the chivalric tradition that he satirizes throughout his novel.
After rejecting his friend Anselmo’s plan to test his wife’s virtue, Lotario uses a series of similes and metaphors to describe female virtue:
The pure, chaste woman is an ermine, and the virtue of chastity is whiter and purer than snow, and the man who wants her not to lose it, but on the contrary to keep and preserve it, shouldn’t do as huntsmen do with ermine [...] A good woman is also like a mirror of clear, shining glass, but any breath that touches this mirror will cloud and dim it. She should be treated like a holy relic, adored but not touched. She should be guarded and prized like a beautiful garden full of roses and other flowers [...]
Here, Lotario uses a series of conventional metaphors, first describing a “pure, chaste woman” as an “ermine,” a small, white, weasel-like mammal. In early modern Europe, it was believed that an ermine would rather be caught by a hunter than dirty its white fur with mud, and so ermine traditionally represented purity and virtue. Next, he describes a “good woman” as a “mirror of clear shining glass." Any “breath that touches the mirror,” he warns, will “cloud and dim it.” Additionally, he notes, in a simile, that a woman should be treated “like a holy relic” that is “adored but not touched.” Last, he characterizes a woman as a “beautiful garden” that strangers are barred from entering. These metaphors and similes reflect the highly traditional and misogynistic perception of Lotario, who believes that a woman is only valuable if she is kept away from other men, whose attention might sully her virtue. Though he praises female virtue and chastity, he nevertheless suggests that these values are easily tarnished.
After Don Quixote praises Sancho Panza for an “affected” speech in which he describes life using an elaborate metaphor regarding chess, Panza uses a series of agricultural metaphors to describe Quixote’s influence on him:
Soil that left to itself would be poor and sterile gives good yields when you manure it and you till it. What I’m trying to say is that being with you is the manure that’s been spread over the barren soil of my poor wits, and the tilling is all this time I’ve been with you, serving you, so I’m hoping to give wonderful yields that won’t be unworthy to be piled up beside the paths of good breeding that you’ve trodden over this feeble understanding of mine.
Here, Sancho characterizes himself, in a metaphor, as soil that if “left to itself would be poor and sterile.” Spending time with Quixote, however, has added metaphorical “manure” to the “barren soil” of his “poor wits.” The longer he accompanies Quixote, he claims, the longer this soil is tilled, and in the end he hopes to gain “wonderful yields” from their time together. Through these various agricultural metaphors, Sancho suggests that Quixote has helped to make him a more lively and intelligent thinker, fueling his own imagination. Throughout the second part of the novel, Sancho becomes increasingly invested in Quixote's fantasies, just as Quixote himself grows more cynical.
After Don Quixote almost starts a fight with a troupe of actors, whose loud bells frighten Rocinante, he speaks to Sancho Panza and uses an elaborate and conventional metaphor that compares life to theatre:
‘Have you ever seen a play that includes kings, emperors, and popes [...]? One actor plays the pimp, another plays the liar [...] but once the play is over and they remove their costumes, all the players are equals.’
‘Yes, I’ve seen a play like that,’ Sancho replied.
‘Well, the same happens,’ said Don Quixote, ‘in the play of this life, in which some act as emperors, others as popes and, in short, all the characters that there can be in a play; but when it is over, in other words when life ends, death strips them all of the costumes [...]’
First, Quixote asks Sancho if he has ever seen a play where actors play characters of different social rank and character. After Sancho affirms that he has, Quixote gets to the point of his speech. Just as actors play different parts but return to their equal status once the play is over, so too does a similar logic operate in “the play of this life.” Though one man might be an “emperor” and another a “pope,” death, Quixote notes, “strips them all” of their respective “costumes.” In the end, he concludes, all are ultimately equal. His speech suggests that there is something artificial about social status on earth, which is distinguished by mere clothing. Sancho, however, later notes that this metaphor is highly conventional, and he isn’t impressed by Quixote’s unoriginal notion.