I would guess that genre wise this would count as fantasy, due to the nature of it and the fact that magic is a predominant part in the novel, but at the same time part of me does not want to class it as fantasy, it is more fairytale. The novel is based on the various versions of the folk tale; the worn out dancing shoes, in which (with some discrepancies depending upon where the tale is told) an old soldier tries to discover how the twelve princesses are wearing out a pair of dancing slippers every night, with the help of an invisibility cloak. When he discovers what is happening he is married to one of the princesses (this normally seems to be the eldest.)
The novel sticks to the basic outline of the folk tale, with the exception that in the novel it is very clear, from the very first page, that the Princesses are cursed and are not as frivolous as they appear to be in some of the folk tales. There are some other differences, such as the soldiers age and that there are only trees of silver (and lacking the gold and diamond trees).
I very much liked the way that, despite it being in third person narrative, and the fact that there are several parts of the novel where it is from the Princesses perspective, you don't actually find out what the curse is, or why the curse is there, or even who is behind the curse, until Galen does. There are clues and teasers throughout, but the suspense that the author builds up is put to good use in that way.
The characterisation fell a bit flat for some of the characters, though that can be expected from something based on a folk tale, particularly when there are 12 princesses (I can't name them all, and am thankful that the author gave at least some of them defining traits to help!), but Galen and Rose in particular did seem to have an interesting amount of depth to them. I did particularly enjoy the fact that Rose wasn't just a simpering Princess wanting to be rescued (and the second eldest Princess, Lily, was even less like that!) and she was seen as acting as a mother and otherwise strong figure for the other girls to look up to.
Like all folk and fairy tales it is obvious what the ending is going to be, and that good will triumph over evil, but in my opinion that didn't make the story any less enjoyable! Well worth a read!