"Berlin. 1963. The height of the Cold War. An early morning spy swap, not at the familiar setting for such exchanges, or at Checkpoint Charlie, where international visitors cross into the East, but at a more discreet border crossing, usually reserved for East German VIPs. The Communists are trading two American students caught helping people to escape over the wall and a lower level CIA operative. On the other side of the trade: Martin Keller, a physicist...

In the masterly hands of Harry Turtledove, this epic chronicle of war becomes a story of human struggle. As the armies of the world implode, the next chapter will be written by the survivors--those willing to rise up for an uncertain future.