Flaubert (“Bouvard et Pecuchet”) and Sartre (La Nausee) have some nice barbs for autodidacts.

But the greatest and most balanced portrait would have to be Don Quixote, especially Part 2, in which the insane (self-taught) fantasist Quixote becomes more sympathetic than the formally learned Sanson Carrasco, who turns out to be Quixote’s nemesis.