According to George R. Stewart, Ish was a survivor of "a fatal plague" that decimated the world's population in the later years of 1944, having missed the action due to falling into a coma after being bitten by a rattlesnake in the Sierra mountains.
As the comforts of civilization start to fall apart (electricity, running water, transportation infrastructure), he and his dog Princess, his bi-racial wife Em, and other survivors learn how to start over. Ish become a patriarch and the symbol of his power is his prospector's hammer, which he had found while in the Sierra Nevada mountains.."If a killing type of virus strain should suddenly arise by mutation...it could, because of the rapid transportation in which we indulge nowadays, be carried to the far corners of the earth and cause the deaths of millions of people." W.M. Stanley, in Chemical and Engineering News, December 22, 1947 [pg 1] http://en.wikipedia.org/wiki/Earth_Abides
Ish fears that much of what he knew and cherished as knowledge will be lost on the younger generation, and puts his trust in his youngest son Joey, who seems to have a knack for book learning. However, young Joey dies in a typhoid epidemic, and Ish descends into a mental fog.
One time, during a moment of lucidity, Ish realizes one of his grandsons, Jack, is standing before him proudly demonstrating that he and the other youth had perfected bows and arrows to the point that they were more reliable than firearms. He realizes that there was nothing of the old world that was of any value anymore.
In the last section of the book, "The Last American," ish is dying.
 The young men had been very respectful and friendly all day. But  now they became irritated. They gesticulated, and Ish could see they were insistent that he should do something, and were even frightened that he might not be able to do it. They made gestures toward the hammer, but Ish did not feel it worthwhile to try very hard to understand.
Soon, however, the young men were even more insistent, and then they began to pinch him. Ish felt the pain because his body was still sensitive, and he cried out, and tears even came to his eyes, though he was ashamed of that, and felt that it was not fitting for the last American.
“It is a strange thing,” he thought, “to be an old god. They worship you, and yet they mistreat you. If you do not want to do what they wish, they make you. It is not fair.”
Then, by thinking hard and by watching their gestures, he thought that they wanted him to indicate one of them to whom the hammer should be given. The hammer had been Ish’s own for a long time, and no one had ever suggested that he should give it to anyone else, but he did not care; besides he wished them to stop pinching him. He could still move his arms, and so with a gesture he indicated that the young man called Jack should have the hammer.
But at least they all seemed to be relieved, now that the inheritance of the hammer was settled, and they did not bother Ish anymore. He rested there quietly then, as if he had done all in this world that he needed to do, and had made his peace. He was dying on the [SF Bay] bridge, and he knew it now. ...
 Then, though his sight was now very dim, he looked again at the young men. “They will commit me to the earth,” he thought. “Yet I also commit them to the earth. There is nothing else by which men live. Men go and come, but earth abides.” http://www.amazon.com/Earth-Abides-Geor ... 0345487133
Go ahead, Stephan, turn THAT into a story about Marcionites.