This is the fourth, and I believe final, book in the Twelve Houses series by Sharon Shinn (here is my review of the rest of the series: The Twelve Houses series). I have enjoyed this series tremendously, as Shinn always does a fantastic job with her characters. The main characters in this series are mystics - people with a variety of magical powers that they believe are bestowed upon them by a variety of gods. Mystics are in danger in the world, as a new cult is spreading, spouting ideas that mystics are evil and need to be destroyed. This fourth book wraps up the conflict that has been brewing in the last three books, ending with a war.
One of my favorite things about Shinn's books are her romances, which are always wonderfully written. The other thing she does very well is creating suspenseful situations, the kind that make it impossible to put the book down, or even to pay attention to anything else that is going on around you - the story sucks you in so completely. This series is a great read for anyone who enjoys fantasy. It even has a satisfying conclusion, so you don't feel quite so bereft that there will not be any more written about these characters. And of course, you can always read some of her other series next.