In the year 2000, a huge potato-shaped asteroid, nicknamed the Stone by Americans, appears in orbit around the earth. Exploration shows that it is divided into seven man-made, hollowed-out chambers, indicating that it had been inhabited. Scientists discover that it was built by Earth people, but in the far distant future, and that a nuclear war is imminent. It becomes crucial that theoretical mathematician Patricia Vasquez discover why the former habitants left and where they went. Although Eon is far too long, its story of futuristic cities and life forms stirs the imagination. Readers travel to worlds where humans may exist as memories in the City Memory Bank, corporeal representatives (ghosts) or incarnations. Other humanoid life forms also exist, and in an amazing array of shapes, from snake-like creatures to floating blobs. Bear's creativity provides a richness to an intricate, complex plot.