Eon

Eon is a science fiction novel by the American writer Greg Bear, published in 1985 and the first of his Way series.

The object arrives while the world is preparing for another nuclear war, and the two superpowers immediately treat it as something to be claimed. Inside, the asteroid is larger than its outside, which is the first of many things about it that cannot be explained, and its terraced chambers hold cities built by people who wrote in English, Russian and Chinese and have been gone a long time. The explorers who enter are a mixed group of scientists and soldiers, and their politics come in with them. Beyond the seventh chamber the stone opens onto a corridor called the Way, which leads to other times and other versions of Earth, and the novel turns from an archaeological expedition into an argument about what humanity is going to do with what it has found.

The book was nominated for the Arthur C. Clarke Award and began a sequence that continued in Eternity.