It's really amazing that McCarthy can combine what's basically a horror tale of wild cannibals with a tender father-son love story. It would take us forever to list all the nasty stuff in this novel, but we'll share a few of the major gross-outs: humans kept like livestock waiting to be slaughtered in a cellar; sex slavery; a human infant roasting on a spit; skulls on pikes. McCarthy doesn't hold back with the violent stuff. In this way, he's very straightforward and unflinching about the consequences of an apocalyptic disaster.
This doesn't stop him, however, from telling a touching father-son story. McCarthy includes plenty of tender moments between The Man and The Boy without any irony whatsoever. He's serious about the love a father can share with a son, even in the wake of a huge disaster.
Much of the novel chronicles what's been lost. Since the disaster struck, no animals have wandered the woods, society has crumbled, and decent human beings have all but disappeared. When McCarthy describes The Man's memories or something that's no longer around, he slips very comfortably into a simultaneously sad and celebratory tone. You might call it (vocab word for you here) "elegiac."
Take a look at the very last paragraph of the book if you don't believe us. McCarthy reserves this for the brook trout that probably no longer exist. Even while McCarthy describes the beauty of the trout, he mourns its extinction. It's a stunning description of loss that makes us want to cry and shoot off fireworks at the same time.
We'd be skimping if we didn't include "factual" as another description of the tone. Sometimes McCarthy will go on at length about how The Man takes apart a stove and rebuilds it, or how he shaves down a cartridge casing to make a serviceable bullet. He clearly cares about the intricacies of "fixing stuff." This gives the novel a factual tone.