One of the great novels set in a post-apocalyptic world, George R. Stewart's
Earth Abides, first published in 1949, has been harvested for ideas countless times. Among the most striking examples of works inspired by this book are
The Stand by Stephen King and the movie
Quiet Earth.
Earth Abides tells the story of Ish Williams, one of the very few survivors of a deadly epidemic that wipes out nearly the whole human population. He and the group he starts building ("The Tribe) have to decide which course to take in the new world they are facing, in which most technological and civilizational skills cannot be maintained by a humanity that turns back to bow-shooting and superstitious cult religion.
Just as he pulled himself up to the rock ledge, he heard a sudden rattle, and felt a prick of fangs. Automatically he jerked back his right hand; turning his head, he saw the snake, coiled and menacing. It was not a large one, he noted, even at the moment when he raised his hand to his lips and sucked hard at the base of the index finger, where a little drop of blood was oozing out.
“Don’t waste time by killing the snake!” he remembered.
He slid down from the ledge, still sucking. At the bottom he saw the hammer lying where he had left it. For a moment he thought he would go on and leave it there. That seemed like panic; so he stooped and picked it up with his left hand, and went on down the rough trail.