This is one of those books where the back story, the history that leads up to the current time of the book, is presented in piecemeal fashion. Sometimes that works. Sometimes that leads to confusion (at least for me it does). That was the case with this book. After reading it, I'm still not 100% sure I know or understand what caused the "apocalypse". (Maybe that's the point, i.e. to get me to read the next book ... lol). Anyway, to the book's credit, I read it to the end. And I plan on reading the next book. So, despite the confusion, the book is a good read.