More Grimm (not to mention grim) than Disney, this collection is made up of poetic retellings of classic fairytales. The story of Cinderella is so well known that it's become a cliché, and Sexton's poem takes advantage of this by remixing the tale to show how empty fairytale endings would be in real society.
Sexton's poem—which uses pretty poetic language but also sarcasm and a bunch of pop culture references—starts by drawing parallels to similar rags-to-riches fantasies, then presents the ugly stepsisters and handsome princes and glass slippers we're all familiar with, then shows how paralyzingly false the whole idea of "happily ever after" really is, hinting at its detachment from the realities of human life. Basically, she questions the concept of the fairytale ideal as a whole.
Unlike the whimsical language typically found in fairytales, Sexton includes lots of references to modern everyday life and concludes that Cindy and Prince Charming end up "like two dolls in a museum case." What does that say about the role of the fairytale ending in contemporary society?