A great book by Cormac McCarthy - The author of No Country for Old Men
Read it before the upcoming movie comes out... ;)
A father and his son walk alone through burned America. Nothing moves in the ravaged landscape save the ash on the wind and water. It is cold enough to crack stones, and, when the snow falls it is gray. The sky is dark. Their destination is the warmer south, although they don't know what, if anything, awaits them there. They have nothing: just a pistol to defend themselves against the lawless cannibalistic bands that stalk the road, the clothes they are wearing, a rusting shopping cart of scavenged food--and each other.