Harbingers is the 10th Repairman Jack novel. This is my second read because the new Bloodline is out and I'm refreshing my memory before I read it. If you've never read a Repairman Jack novel you're in for a treat, but I recommend starting from the beginning. I think there are 11 total now. You can see an earlier post of mine on Crisscross for a link to a list of all the novels in order.
This story brings a whole new set of characters into the battle between Jack and the Adversary. The problem is figuring out if their friends or foes. There's plenty of action and some big surprises. Very highly recommended.