"What we have here, he realized, is not an invasion of Earth by Proxmen, beings from another system. Not an invasion by the legions of a pseudo human race. No. It's Palmer Eldritch who's everywhere, growing and growing like a mad weed."

Philip K. Dick's paranoid masterpiece. The fragility of reality was long a preoccupation of Dick's, and here it finds perhaps it most insidious expression, as a new mind-altering drug from an explorer just returned from a distant solar system is more than it seems. There are heavy religious overtones, presaging Dick's metaphysical turn of the late 70s after his self-confessed psychosis. In fact, the book is arguably about the coming of space Jesus, and how an encounter with a truly divine messianic being would be existentially terrifying.