The Paradox Planet

From the front flap of the Doubleday first edition: "Elias Kane: Ex-Space Navy, gambler, private investigator... and hero. Kane always felt that being a hero had been an accident. He'd saved the life of the Imperator, Gregory Amerdath. Billions of citizens on dozens of worlds saw Kane as the consummate hero. But Kane would have given up the fame, the adulation, the glory - even the warmth and friendship of Amerdath's daughter and the new Imperator, Briana, if it would have brought Beth Tyson back to life. But the death of his beloved Beth, and his subsequent triumph of solving the mystery of Amerdath's near assassination-suicide, was irrelevant. Briana had sent for him, to give him a mission on Cassiodorus, the colony world where the rare and vital beta-steel was mined. So far, three imperial inspectors in a row had disappeared while inspecting the mines. However, Kane's task on the high-gravity planet was more than an investigation of possible murders. He also had to try and discover if rebels were stealing the ore for use in building a fleet of dreadnoughts to fight Earth's own. Once there Kane, his friend and resourceful ally, the giant Cephantine named Pendrake, and Martha Reik, a doctor and scientist with whom Kane was falling in love, become the targets of the nameless rebel murderers who felled the inspectors. But what they discovered about Cassiodorus and its powerful inhabitants was far more deadly than any murder weapon. The evil they uncover could prove the undoing of more than one planet and, possibly, the empire."