Silence is Deadly — Lloyd Biggle Jr.

Twenty agents of the Galactic Sythesis are missing on the Silent Planet of Kamm -- the victims, it seems, of the most powerful death ray the universe has ever known. But how could the primitive technology of the Kammians have produced such a weapon? And why would they unleashed its power against the Sythesis? It's Jan Darzek's mission to find out...