mass market paperback
English language
Published Sept. 11, 1987 by Del Rey.
Until the arrival of Aiken Drum, the 100,000 humans who had fled backward in time to Pliocene exile on Earth knew little but slavery to the Tanu, the humanoid aliens who came from another galaxy. But King Aiken's rule is precarious, for the Tanu's twisted brethren are secretly maneuvering to bring about his downfall. Worse, Aiken is about to confront a man of incredibly powerful talents who nearly overthrew a galactic rule. He is Marc Remillard. Call him...The Adversary.
Rating and date are for second reading.
