The novel's structure is in episodic form. It is written in the picaresco style of the late 16th century, and features reference other picaresque novels including Lazarillo de Tormes and The Golden Ass. The full title is indicative of the tale's object, as ingenioso (Spanish) means "quick with inventiveness" marking the transition of modern literature from Dramatic to thematic unity. The novel takes place over a long period of time, including many adventures united by common themes of the nature of reality, reading, and dialogue in general.
Although burlesque on the surface, the novel, especially in its second half, has served as an important thematic source not only in literature but also in much of art and music, inspiring works by Pablo Picasso and Richard Strauss. The contrasts between the tall, thin, fancy-struck, and idealistic Quixote and the fat, squat, world-weary Panza is a motif echoed ever since the book's publication, and Don Quixote's imaginings are the butt of outrageous and cruel practical jokes in the novel.
Even faithful and simple Sancho is forced to deceive him at certain points. The novel is considered a satire of orthodoxy, veracity, and even nationalism. In exploring the individualism of his characters, Cervantes helped move beyond the narrow literary conventions of the chivalric romance literature that he spoofed, which consists of straightforward retelling of a series of acts that redound to the Knightly Virtues of the hero. The character of Don Quixote became so well known in its time that the word quixotic was quickly adopted by many languages. Characters such as Sancho Panza and Don Quixote's steed, Rocinante, are emblems of Western literary culture. The phrase "tilting at windmills" to describe an act of attacking imaginary enemies, derives from an iconic scene in the book.
It stands in a unique position between medieval chivalric romance and the modern novel. The former consist of disconnected stories featuring the same characters and settings with little exploration of the inner life of even the main character. The latter are usually focused on the psychological evolution of their characters. In Part I, Quixote imposes himself on his environment. By Part II, people know about him through "having read his adventures", and so, he needs to do less to maintain his image. By his deathbed, he has regained his sanity, and is once more "Alonso Quixano the Good".
When first published, Don Quixote was usually interpreted as a comic novel. After the French revolution it was popular for its central ethic that individuals can be right while society is quite wrong and seen as disenchanting. In the 19th century it was seen as a social commentary, but no one could easily tell "whose side Cervantes was on". Many critics came to view the work as a tragedy in which Don Quixote's idealism and nobility are viewed by the post-chivalric world as insane, and are defeated and rendered useless by common reality. By the 20th century the novel had come to occupy a canonical space as one of the foundations of modern literature.