The Time Traders is the first novel in The Time Traders series by Andre Norton. It was first published in 1958, and has been printed in several editions. It was updated by Norton in 2000 to account for real world changes. It is part of Norton's Forerunner universe. The Time Traders introduces the series' premise, a confrontation between Western heroes, and the "Reds", and a mysterious alien race that has used time travel to alter Earth. This novel alternates among the present day, a trading tribal society in Britain, 2000 B.C., and a glacial outpost in the last ice age. In her Time Trader novels Norton tacitly assumes that the physics of time travel differs so significantly from the physics of space travel, especially hyperdrive-propelled interstellar flight, that a civilization that discovers the technology of one simply will not discover the technology of the other. Earth's physicists have discovered the secret of time travel, but the engineers and scientists who built and use the time transporters have devised a clever way to obtain the secrets of space travel: if we can't discover the secrets for ourselves, we will get them from someone who did.