The Time Traders

The Time Traders is the first novel in The Time Traders series by Andre Norton, published at the height of the Cold War... A conflict forms between Western heroes, and the "Reds", and a shadowy alien race that has used time travel to modify Earth. The story alternates among the present day, a trading tribal society in Britain, 2000 B.C., and a glacial outpost in the last ice age. Essential listening for fans of the fantasy sci-fi genre!