This is Book 3 of the Dresden Files.
This series just keeps getting better and better. I really enjoyed the addition of a new character, Michael. He is a God-fearing, giant-sword-toting family man. He can also hold his own in a fight.
In this book the plot gets a lot more complicated. There is no shortage of action, political intrigue, mortal and spiritual danger, moral quagmires, kidnapping, and a lot of fighting. In addition to all of that, there is a very nasty ghost on the loose who is terrorizing people in their sleep. And those people happen to be Harry's friends.
Harry continues to develop as a character and continues to get himself stuck in impossibly complicated situations. This is a must-read book in a must-read series and I highly recommend it.