A short book (200 pages) that seemed even shorter. We already know the characters from _Every Heart a Doorway_, and this prequel goes into how Jack and Jill became the characters that they are in that first book. This doesn't work well for a couple of reasons. One is that the original characters are both kind of one-note; there isn't a lot of deep mystery to them that we were dying to uncover. They each have their one conversational tic and motivation, as would any NPC that my code would generate. A second problem is that the novel spends a lot of pages scene setting and not much in actually developing character. For a 200 page book, there are not that many events, and really only like 3? 4? things happen in fairy land. It seems like we already know the starting point of the story (they are born) and the ending point (they come back from fairy land in their one-note state), and not *that* much seems to happen in between.
On the plus side, the author isn't terrible, I liked the little world building that goes on in the Moors, and I agree with the author's general moral of letting people develop and flourish in their particular fashion rather than according to strict roles/genders. All in all it is very YA.