The Border

Robert McCammon returns to the apocalyptic horror of his earlier Swan Song and Stinger with a novel about an Earth wrecked by war between two alien civilizations. The Gorgons fly living ships; the armored Cyphers send shock troops that move in a blur. At Panther Ridge, a human stronghold, the few survivors face a world that has turned against them: some give way to despair and suicide, while others are changed by alien pollution into Gray Men, cannibal mutants with an endless hunger. Then an amnesiac teenage boy arrives and names himself Ethan. He is met with mistrust, and his unexplained powers may prove to be humanity's last hope.

Stephen King called it rollicking old-school science fiction, with nasty aliens and heroic humans, and said he dug it.