you dont neeeeeed the survival guide. but that book allows you to have a better sense of what the zombie is and how dangerous they are. i would really recommend reading survival first so you can better appreciate the interviews and what they went through to survive. so yes survival first then this one! : )
What!? YES you need to read The Zombie Survival Guide! What if there is a Zombie outbreak and you're unprepared?! You all should OWN your own copy of it.
If you don't get it, when the Zombie's attack, don't come crying to me and try to break into my Zombie Proof home! Nuh uh! You'll just end up doing something stupid to get me killed.
Seriously though, I would recommend reading it either Before World War Z or along with. I read mine along with and I found myself going through the book and citing what the people in World War Z did wrong, like, "If only they had read Chapter 4! They would have known they shouldn't have done ____!"
Both are really well written and thought out books and I would be surprised if the strategy eggheads in Washington don't have at least one copy they've all glanced over, 'Just in Case.'
Incidentally, the Zombie Survival Guide could also be used as a Virus Outbreak Guide because of the similarities.