It's really good! I just recommended it to my friends too. I was quite sad the book ended without the story finishing, but I can't believe I was actually reading it at the right time so it will coincide with book 2's release.
I was just thinking though, seeing some of the pics in the book...as an idea (not sure if it was discussed already here), I think it would be super cool if one of the theories/premises is somehow the internet survived without going down (or a similar story to DBDA within the first few weeks before systems go down), and the journal/diary was written online as a blog post, with the odd pics and some other goodies like short video clips to make it more interactive. I've noticed that there are some preteen books that have followed this newer style of story-telling, but I was just thinking that this would be really cool for a zombie book that's in journal format.
Just my 2 cents.
Keep up the good work!
