Justin E. H. Smith in his own blog:
Nabokov said its humor did not age well, and unlike Moby-Dick, which is occasionally dismissed as a school-boy's adventure story but never as hokey or stale, The Ingenious Gentleman Don Quixote de la Mancha seems to suffer under the weight of its most representative scenes. The association of the whole with these mere parts is either too vivid, or it is not vivid at all, as in the case of the subnovel of Anselmo and Lothario, which everyone today knows, without knowing where it is from. Most of these scenes are played out in Part I, by the end of which the presumed hero has survived several battles against hallucinated enemies, drawn his squire hesitantly but hopefully into all of them, and mingled with several different minor characters, many of whose own stories, and not just Lothario's, amount to novels within the novel. He has been tricked into a cage by a sympathetic pair, a canon and a priest, and taken back to his home, to his housekeeper and his niece, in the hope that he might be cured of his madness.
Part I was published first in Madrid in 1605, and over the next ten years would be published in Brussels (1607), Milan (1610), and, in the first of many English translations, in London in 1612. Part II would be published ten years after Part One, also in Madrid, in 1615. Although Don Quixote is so often reduced to the battle with the windmills, which has been concluded within the first few chapters of Part One (leading us to suspect that its iconic character has at least something to do with the fact that many readers get no further), it is Part II, and what happens or is imagined to have happened between 1610 and 1615, that is the true clavis to understanding the novel in its entirety, and in all its philosophical, subversive, deceitful greatness.