This Kindle book also:

Wasteland Survival Guide

For anyone interested in free zombie books on the Kindle, we have an active topic over on GoodReads that posts a few almost every day:

https://www.goodreads.com/topic/show/824495

Many of the offerings are only free for a single day, because of how the KDP program works.

That Goodreads group also has a number of group reads each month.