If you're curious about it, Kunstler offers his own bullet-pointed summary of his own book on his blog. I don't find much of his scenario plausible, particularly his prediction that an energy shortage will be the death of the entertainment/media industry. Producing movies, music and tv is really a labor intensive, not an energy intensive, enterprise. With today's technology, a great deal of entertainment content can be produced with high standards of quality using small amount of capital, physical resources and energy. Video cameras and similar equipment don't require much electrical energy to operate.
I think what's apparent about Kunstler is that he isn't very well grounded in science and engineering. He's a misanthrope who hates modern culture and not so secretly hopes his peak oil apocalypse will be a kind of secular Noah's flood, punishing us for our decadence and forcing some kind of return to moral rectitude.