Time's Eye — Arthur C. Clarke; Stephen Baxter

In an instant, Earth is carved up in time and reassembled like a huge jigsaw puzzle. Suddenly the world becomes a patchwork of eras, from prehistory to 2037, each with its own indigenous inhabitants.

The explanation for this cataclysmic event may lie in the ancient city of Babylon, where two groups of refugees from 2037--three cosmonauts and three U.N. peacekeepers--have detected strange radio signals. The peacekeepers find allies in nineteenth- century British troops and in the armies of Alexander the Great. The cosmonauts join forces with the Mongol horde led by Genghis Khan. Both sides set out for Babylon, vowing to win the race for knowledge--as a powerful and mysterious entity watches, waiting.