The disappearance of one of Jupiter's moons, the appearance of "little green men" in Australia and the American Southwest, and the sudden presence of unidentifiable objects on a collision course inside the Earth's core add up to the inescapable conclusion that the Earth has been invaded by an enemy it cannot fight. Powerfully and gracefully written, the latest novel by the author of Eon and Blood Music stands far above most examples of "doomsday" science fiction