I just finished this book last night. Set in the early 1800s in England during the Napoleonic Wars, its literary style echoes that of the period. It proposes an alternate history where English magic is an actual fact and is used to assist Lord Wellington in defeating Napoleon. There is much more to the story than that, as well there should be in a book that runs on to 782 pages or thereabouts.
That is my primary complaint, that the length is excessive. I did make myself read it all the way through because it is rare that I do not finish a book, and I did want to see how this one ended. It features a dry sense of humor and a sense of secrecy that draws one in, but as one knows all the way through the solution to the mystery that one of the characters is trying to solve, it tends to drag on.
Another intriguing stylistic feature is the use of footnotes to tell most of the fairy tale "history" rather than integrating it into the narrative. I can recommend it to those who have patience in reading and are interested in a new approach to the fantasy and magic genres. It has a dark, understated way of telling the story that does not evoke visions of Harry Potter and the like and is definitely adult.