I think my favorite fantasy-not-fantasy book (and probably one of the books that influenced me the most as a young, book hungry girl) is C.S. Lewis’s Till We Have Faces (pleeeeease ignore the awful cover art on this version). It’s a retelling of the myth of Eros and Psyche as told by one of Psyche’s sisters, who in the myth is the faceless, bitter source of Psyche’s doubt, but in Till We Have Faces is the infinitely flawed and interesting Orual, an ugly princess who comes to rule her country in her own right as a masked queen.
For whatever reason, the story is never marketed as a fantasy, never labeled that way, but it’s always been a fantasy for me. There’s some vague pretense to history, but it’s mostly a created kingdom that reminds me more of Ursula LeGuin’s creations than a historical novel. The mythical and the mundane mix as freely as any gods and mortals in more traditional fantasies, and even more, the characters have that richness, that other-worldly sameness that defines fantasy in my mind.
If you haven’t read Till We Have Faces, please go give it a try. It’s more true, adult fantasy than anything else Lewis wrote, and it is a truly phenomenal story of personal blindness, and how we can hurt those closest to us when all we want to do is protect them. Truly epic, beautiful stuff.