WARNING: Mild spoilers ahead
I was really looking forward to reading Directive 51 after it was mentioned in the Atlantic's article re: cyberwarfare. I'm a sucker for end-of-the-world scenarios and I'm usually profoundly disappointed with their execution (2012, I'm looking at you). This book, sad to say, was no different.
The premise is interesting and had real potential for making a gripping novel about the end of the modern era and how people would cope with a disaster that wiped out everything we relied upon for the functioning of our society. Unfortunately, the characters you have access to are emerge relatively unscathed from the disaster and you are therefore not really exposed to the breadth and depth of the horror.
The book focuses almost exclusively on the members of the federal government charged with forecasting future threats, who then become the heads of state when the disaster takes hold. As such, they aren't really affected by the loss of power, of food, of clean water, of all modern conveniences. The book references entire cities burning to the ground, millions dying of starvation during the winter, thousands freezing to death while fleeing cities... but those events are presented when the main characters present "reports from the field" to other members of the government. You get no on-the-ground experiences of what it's like for people actually living through the event. The members of the government are cloistered in protected compounds with supplies of power, food and water. You're totally detached from the "reality" of the situation for 99.999% of the Earth's population and, as such, it's snooze-ville for disaster enthusiasts.
In addition, the plot itself suffers from a lot of weak spots. The connection between the main saboteurs and the Islamic terrorists is weakly explained and eventually just left for dead. The ability of hobby enthusiasts to resurrect dead trades and get museum-piece locomotives working seemed a bit too convenient and easy. And then, just when you think it can't get more implausible, the author throws in EMP bombs assembled by self-assembled robots on the moon and launched back to Earth... out of the blue, without much explanation at all of how they got there in the first place, who was involved with that segment of the conspiracy or really any explanation. It was the last straw for me.
To add insult to injury, the author falls back upon just about every tired end-of-the-world trope in this book. Sure, the main characters are an overweight redhead and a disabled man, instead of the usual pretty people that populate these books, but the author still gives us the same old romance between the two protagonists.
My verdict: Give it a miss, or wait for the inevitably bad movie.