The Remaining by D. J. Molles.
The Remaining is the first book in the bestselling series and it is not bad at all! It helps if you are interested in weapons though. Guns are described with so much obsessive detail, one starts to wonder a little… Nevertheless, the loneliness of the main man Lee, a soldier under orders to wait underground in a bunker, is truly palpable and adds to the excitement before mayhem starts. And he has a dog – for me always a plus in any book!
It has 131 (and rising) 5-star reviews on Amazon – nobody has that many friends who fake reviews (recently I started to wonder about that last statement…?). So a popular book with an interesting beginning.