I'm certain that Lisa's Take will give you more detail, but here are my thoughts...
I didn't really want to like this book. Well, that's not entirely true. Rather, I should say that after the first 30 pages I was pretty convinced that I wasn't going to like this book. I even put it down for several months at that point. Here's why: The first section of this book feels like a Victorian romance novel. Although entertainingly written, it had me utterly convinced that I was about to have to sit through nearly 800 pages of a poor repressed woman's burgeoning sexuality in the hands of her whip weilding new lover(s). Seriously. I challenge you to read 35 pages and think otherwise.
So a few months pass, and I pick the book back up because Lisa *insists* it's worth my time. She tells me that I need to at least read the first point of view chapter for each of the three characters. This was a very sneaky thing to tell me, it turns out, since that takes you about 300 pages. Sneaky or not it was good advice, though in truth I was thoroughly hooked by the beginning of the second character. The writing is phenomenally entertaining, and the characters are unique and engaging.
First you have Celeste, who manages to not burgeon after all, which is probably for the best. She's a strong character who does not, in truth, take shit from anyone. Next we have "Cardinal" "Chang" a mercenary of a philisophical bent with a snazzy coat and very little sense of self preservation. Finally, we've got Doctor Svenson. He's not a great secret agent as it turns out, but a dandy doctor and entertainingly conflicted about everything he's ever encountered. The three of them, for reasons that are tenuous when viewed out of context, get involved in a plot to take over the world using Creepy Science. Hijinx ensue.
This isn't the first book I've read recently that I was tempted to describe as a book about sex in which nobody actually has any, but in this case the description is unfair. Better to say that this is an awesome Victorian adventure/mystery/fantasy novel with some sexual overtones. The pace of the book never lets up despite its intimidating length, the characters are consistant and fun, the world is fascinating, the fantasy elements are introduced sneakily and blend into the world seamlessly.
Basically, I highly recommend it.