There are 4 books in the Day By Day Armageddon series. The newest book is Ghost Run which came out in 2016.

2
Beyond Exile

Book cover of Beyond Exile
Sporadic news reports indicate chaos and violence spreading through US cities. An unknown evil is sweeping the planet. The dead are rising to claim the Earth as the new dominant species in the food chain. This is the handwritten journal depicting one man's struggle for survival. Trapped in the midst…

3
Shattered Hourglass

Book cover of Shattered Hourglass
The world lies in ruins...humanity's last stand is underway...the dead have overtaken the living as the new dominant species. Day By Day Armageddon: Shattered Hourglassexpands upon the critically acclaimed series of the zombie apocalypse, and alternates between the handwritten journal depicting a military personnel's struggle for survival and the survivors…

4
Ghost Run

Book cover of Ghost Run
The acclaimed and eagerly anticipated fourth thriller in the zombie apocalypse series from the author of Day by Day Armageddon and Day by Day Armageddon: Beyond Exile, for fans of the smash hit show The Walking Dead.
In a desperate bid to survive as hordes of bloodthirsty undead now dominate…