The concept is solid PKD- wealthy elites engineer a phony war to drive the underclasses into massive underground shelters, where they live short, crowded, terrorized lives. Meanwhile the Earth's surface becomes a veritable wildlife park for the few who live there in peace and prosperity. It has a little bit of a Morlock/Eloy vibe, but also has whispers in reality, namely in Rewilding North America, Dave Fpreman's "Rewilding Institute", and other flavors of militant environmentalism that call for proscribing mankind from large chunks of the planet (well, at least riff-raff like you and I; I'm sure the Rockefellers will be able to go anywhere they like...)So why did I only give this book three stars? It's kind of clunky. All of the characters are underdeveloped (a consistent weakness of PKD), and the ending wraps up a bit too neatly and easily. Worth the read- you can blow through this in no time.