Lord Tedric (version 2) by E. E. Smith

The best of science fantasy meets the best of science fiction as Tedric battles his way through two universes of adventure: In one universe...Tedric the Ironmaster wields the mightiest sword his world has ever seen - and swears to break the power of the evil god Sarpedion, or die in the attempt. This is the second in a series and takes place when Tedric, now a Lord, begins learning how to plan and observe instead of just rushing in to kill. In another universe...only Tedric's strength and daring stand between the dwindling power of the Terran Empire and total alien conquest. Brought from his own distant world by the mysterious Scientists, working toward an end he cannot know, Tedric brings the war-wisdom of his own past into a universe of starships and alien powers. But that is for future books in the series. On Time Track Number Two however, there was one little event that could be used to avert it—the presence of a naked woman in public. So, Skandos One removed the clothing from t