Die Bestie

Pendrake had stumbled into a land whose inhabitants were picked up at random by a time machine. They came from many centuries, but they had one thing in common; they submitted, out of fear, to the rule of the most brutal and primitive among them...The Beast. He looked like a creature out of the primeval jungle, hairy and naked except for the black fur strip that hung around his belly. With no weapons but his superior intellect, Pendrake had to fight to stay alive -- at least long enough to rescue his wife from the savage grasp of The Beast.