Absolutely outstanding writing. I'm always impressed when an author can tell a story I can't help but respect and enjoy, even when I don't really agree with the philosophy, themes, or messages it expresses.
Creatures of Will and Temper is the story of two sisters in Victorian England growing into themselves and finding their place in the world. It has a highly unique, essentially amoral take on demons, and some excellent trickery in its direction, setup and twist. I almost stopped reading at the beginning, as it does open with a scene that doesn't involve either of the sisters, but rather a middle-aged lesbian demonologist, which made me think I wouldn't be interested in the story, but then things broadened rather.
This was a good effort as far as historical fiction goes; even the linguistic style lends itself to period writing (as opposed to the anachronistic use of too much modern language), and historical worldbuilding and background detail was flawless. Very interesting and well-explored human relationships, flaws and proclivities.
There is very strong homosexual (male and female, possibly implied bi) content, so if that's not your thing, be warned. Not too much highly explicit content, intimate scenes are mostly fade-to-black.
As far as historical fiction goes, it's an interesting angle on the more bohemian elements of Victorian society, and extrapolates that amoral and artistic attitude in a new and creative direction. In my opinion, a worthwhile and entertaining read whether or not you agree with the conclusions the author heads toward, and extremely well written.