In a parallel world in which Neanderthals, rather than homo sapiens, became the dominant intelligent species, a dangerous scientific experiment traps a Neanderthal physicist on Earth.
In the twenty-second century Earth obtains limitless, free energy from a source science little understands: an exchange between Earth and a parallel universe, using a process devised by the aliens. But even free energy has a price. The transference process itself will eventually lead to the destruction of the Earth's Sun—and of Earth itself. Only a few know the terrifying truth—an outcast Earth scientist, a rebellious alien inhabitant of a dying planet, a lunar-born human intuitionist who senses the imminent annihilation of the Sun. They know the truth—but who will listen? They have foreseen the cost of abundant energy—but who will believe? These few beings, human and alien, hold the key to Earth's survival.
It's America in 1962. Slavery is legal once again. the few Jews who still survive hide under assumed names. In San Francisco the I Ching is as common as the Yellow Pages. All because some 20 years earlier the United States lost a war--and is now occupied jointly by Nazi Germany and Japan. This harrowing, Hugo Award-winning novel is the work that established Philip K. Dick as an innovator in science fiction while breaking the barrier between science fiction and the serious novel of ideas. In it Dick offers a haunting vision of history as a nightmare from which it may just be possible to awake.