Character Development: B+
Cover Art: A
A lot of people who hated the book seemed to do so because they went in expecting a horror or ghost story based on the floating girl on the cover. The blurb is VERY vague, so it's understandable that readers wind up drawing their own conclusions about what to expect and getting let down.
However, the blurb is vague because letting plot points out spoils the mystery and some of the fun of the book, so I'll try to also be vague in this review!
I loved the atmosphere in this book: murder most foul, dreary weather, the Welsh countryside, abandoned houses, monsters, supernaturally talented children, light necromancy... The first half of the book had me thoroughly creeped out. That said, it's not a horror story. It has much of the Gothic ambiance of The Monstrumologist but without the guts-n-pieces factor. Of course, much of the creepiness comes from the vintage photographs sprinkled liberally throughout the book. This is definitely not a book that you'll be able to appreciate as easily on an e-reader. Go for the physical version for better image quality. And don't do that thing where you just look at the photos before reading the book. You'll ruin stuff.
The book does lose a lot of its atmosphere after the hero learns the secret of the peculiar children halfway through the book. However, the action picks up at that point, and the author has several characters to introduce and develop, a world to explain, and relationships to create. The world-building is well done. A few minor details aren't explored, but they seemed like loose threads left for the rest of the series to tie up later. And don't worry, despite what you may hear, it isn't that much like the X-Men.
My only real complaint about the book is that, on a 1-10 scale of awkwardness with 1 being "kinda off" and 10 being "AWKWARD," the love story in this book is a 17. It probably could have used more development, you know, to alleviate the gross factor.
Extra credit: The hero spends the book learning the true story of his murdered grandfather's life. My grandfathers weren't murdered, but both are passed and gone, and it would be cool to run into a bunch of people who could tell me about what they were like as young men.