All that _didactic_ means, etymologically, is “instructive” or “skilled at teaching” (_OED_: διδακτικός). That meaning has persisted, neutrally, in some languages, where a _departamento de didáctica_ or _département de didactique_ simply refers to an education faculty, or _Didaktik_ labels the theory of teaching. But the term, today, in English, is generally used polemically. To call a children’s book didactic is to accuse it of trying to impart a “message”—generally of a moral nature. _Didactic_, in children’s literature criticism and reviewing, is often synonymous with _moralizing_, _authoritarian_, _totalitarian_, _propagandist_. The term is also its own superlative: rarely is a book deemed “too didactic”; _didactic_ generally suffices to condemn it. Yet “the didactic” (or didacticism) remains seldom defined in children’s literature criticism: it is an I-know-it-when-I-see-it sort of vice. The only solid definitional anchor for didacticism is historical. Didactic literature for children—namely, for religious and moral instruction—was the origin of children’s literature itself: didacticism is in the DNA of children’s literature (Grenby 2009). François Fénelon’s _Télémaque_ (_Telemachus_; 1699), traditionally acknowledged to be the earliest example of children’s literature in the West, was written to entertain but also educate intellectually and morally the young Duke of Burgundy. In the seventeenth and eighteenth centuries,...