This is the first of these Bluejay Special Editions with PKD on the cover I've seen where he's not really supposed to be a character in the book. But notice Dick's face stands between an idyllic pastoral setting and a scene of nuclear annihilation, suggesting both that a fiction (symbolized here by the face of the author of the larger meta-fiction) separates the underground dwellers in the novel from the surface above, and more implicitly suggesting that an author's dystopian vision can deter a world on the brink of nuclear annihilation. (Or I suppose reading right to left, it could be seen to inspire doomsday)
Thomas Disch's book The Dreams Our Stuff is Made From has a chapter titled "How SF Defused the Bomb" and he devotes several pages to Dick. Disch writes:
Of those eight novels [The Man in the High Castle, Dr. Bloodmoney, The Game Players of Titan, The Simulacra, Clans of the Alphane Moon, The Penultimate Truth, The Three Stigmata of Palmer Eldritch, and The Zap Gun], The Penultimate Truth, while far from the best [everyone's a critic], represents his final statement on the nuclear arms race."
Disch then quotes a passage from The Penultimate Truth in which an upper-class, surface dweller explains his success at the expense of the "tankers" who live underground. He says his purpose is:
"to augment our retinue which wait on us, follow us, dig for us, build scrape and bow...you've made us barons in baronial castles, and your are the Nibelungen. the dwarves in mines; you labor for us and we give you back -- reading matter."
I think Dick was an activist writer. I think he wanted to change the world by showing you some worse case scenarios. Of course he wasn't afraid to laugh at potential annihilation, but that makes it palatable. The Penultimate Truth illustrates the way the giant red button makes slaves of all who cannot control when it is pushed.
