This book started a bit slower than the others in the series, but it didn't finish that way. The villains were terrifying, and so were the heroes for that matter. One major plot device was so horrifying that I couldn't believe it was real, even though I looked it up several times. Stross has a disturbing knack for seeing actual horror in the actual world, which really adds to the creepiness. Like the others in the series, this book requires close reading, but still manages to be a fast read with lots of action.

Definitely read the other books in the series first. They are well worth reading and establish the main character and his fellows inthe Laundry, who changes a lot from his first mission to the start of the current book.