This is a moving, thoughtful novel with a terrible title. Yes, it's a retelling of Cinderella (purporting to be the real story), but instead of arguing that Cinderella is secretly a bitch and the stepsisters were the true heroines, it is a meditation on beauty, trauma, and survival.
In this sense it reminds me of Till We Have Faces, C.S. Lewis's retelling of the Psyche and Eros myth. They both deal with women who have an unearthly beauty and sisters who are labeled ugly, and they both refuse to portray any of the main female characters as villains. The stepmother in Maguire's book, the closest the story has to an antagonist, does monstrous things but is no monster; she is a mother hardened by adversity and struggling to provide security for herself and her daughters.
It's the youngest daughter, Iris, who narrates the story, and she's caught between childhood, and the fanciful stories she tells herself, and adulthood, when she must come to terms with the strictures placed on women. She is convinced she's ugly and expects nothing of her future until her mother begins working for a master painter. He and his assistant show her other ways to look at the world, and spark in her an appreciation of the power of art.
Which is no small thing in this world (Haarlem of the 1600s). The Master laments the Protestant, business-like Dutch and their failure to appreciate the profundity of religious art. He hides his paintings of the freaks and oddities of humanity, lest they cause too much outrage amongst the conventional. And his masterwork, a painting of the Cinderella character (Clara), is able to inspire love, lust, business deals, jealousy, and artistic despair.
Clara, meanwhile, wants nothing to do with her beauty, having been traumatized as a young child and then stifled by overprotective parents. She's not the obedient (and personality-less) girl of the original story, but simply another young woman who has been controlled and told what to do her whole life, and rebels in the only way she can.
There's an unnecessary "twist" at the end that causes us to reconsider what we have been told about a character, but it ultimately doesn't add anything to the narrative. Overall, though, I enjoyed this melancholy tale.