I thoroughly enjoyed this one - I love a gothic novel and boy does this deliver.  This book has everything: magic, math, the occult, a crumbling mansion, the ghost of a first wife, medicine, an alternate version of England.  It's all jammed in there.

Other reviewers had problems with pacing; I didn't find it a slow start, but could have used like three more pages in That Chapter to make things a bit clearer.  I don't have a head for fantasy and a math-based magic scheme is designed specifically to thwart my understanding of it, so I could have used a little more exposition.  But wow if this book doesn't just beg to be read in front of a roaring fireplace as rain pounds the windows.

Thank you St. Martins & NetGalley for the ARC!