The most powerful part of this story is what the author doesn't say.
A man and his boy are traveling alone in a post-apocalyptic world. The skies are filled with ash, the air is poisoned by fumes, meals are few and far between, and they must constantly be on the look-out for the bad guys - men who will kill and eat you. They constantly cycle between painfully hungry and one day away from starvation, refusing to give up and determined to get to the ocean where the man believes life will be easier. They have a gun with a single bullet but it becomes shockingly clear that the bullet isn't for potential attackers, but to give the man or boy the only true protection from this devastating world...death.
While there isn't a lot that the reader knows about this world - How did it become this way? How long have the man and boy been traveling? Where are they geographically located? - I think these unsaid facts are the most important part of the story. The answer to all of these questions is the same: It doesn't matter. Regardless of any external factor, the only thing the man and boy are concerned with are living another day, putting one foot in front of the other to take them one step farther down the road. The only thing keeping them going is their love for each other and their blind faith that there is some form of goodness still in the world and that they carry a part of that with them.
This book was not uplifting, did not inspire hope, and did not provide a reason to turn the pages. However, the powerful writing made you feel desolate, hopeless, and strangely determined to keep going in spite of those feelings; the hallmark of a truly phenomenal book is inspiring emotions that reflect the feeling of the story...and McCarthy did that brilliantly even though I didn't want to feel that way.