Dying Days 4 is the fourth book of the Dying Days series written by Armand Rosamilia. In some ways, it is difficult to predict what you will read from one book to the next, which seems like a good thing, but not always. One of the things that makes zombie apocalypse narratives attractive are the specific tropes that characterize the sub-genre. There will be survivors that must contend not only with the unstoppable force of zombies, but also with contending groups of survivors that want your stuff.
Here, Rosamilia gives you that, but also more that I'm not sure what to feel about it. There are smart zombies along with the dead heads, and the smart zombies look down on the dead heads, because they haven't yet evolved. I'm not sure whether Rosamilia is writing himself into a corner but to be honest I feel terrified because I begin to sense human extinction as a very real end.
Because this book is a continuation of a series, I don't think you can just read this as a standalone. To me it seems clear that Rosamilia has a specific end in mind that I am not yet privy to, but I have the entire series of books so, I will eventually read through. Again, the lack of predictability is a double-edged sword.