the concept of the book is interesting - it is basically stating that the survival guide was just the facts about zombies and how to survive against them, but world war Z is the stories behind it all. written from several different perspectives of people from different parts of the world at different times, it's impressive that the author takes on so many personas to write from. it all revolves around how the zombie phenomenon started, ravaged the earth, and humanity's eventual strategic fight back against the undead.
it started off kind of slow, but once the reader realizes that the book is not necessarily primarily about the zombies, but the conflicts of man rather, it becomes a much better book. zombies essentially act as the catalyst for all of the chaos that ensues.
given the slow start-off, i would be inclined to give world war Z a solid 4.5 out of five severed zombie heads with crushed-in skulls with brain juice leaking out of them.