For starters, it is definitely advisable to read this series from the first book onward in order to be in touch with the continuity.
This latest installment took me a while to read, but for good reasons. I was savoring this one. It is written the way a good steak is perfectly cooked and seasoned.
The author's writing skill, which was good to begin with, had been honed with every book that has been released as time goes by. The character development, scene description, and flow of the story will not disappoint.
As far as City of the Dead, I'm not going to give out any of the tasty morsels. You'll need to gather your courage, and turn the pages on your own, if you dare. It is entertaining, scary awesomeness at its finest. Bring a friend.