Clans of the Alphane Moon — Philip K. Dick

Holding a precarious liberty as the result of an interstellar stalemate, the human survivors of Alpha Centauri's hospital moon readied themselves for their war of independence.

Naturally, the Pares, always suspicious and cunning, assumed the leadership, leaving it to the Manses to provide the super weapons out of their sheer love of violence. Propaganda and other details would have to be left to the Skitzes, the Heebs, the Polys, and the Ob-Coms.

But when the Earth expedition arrived, everything turned out to be different . . . because they too were divided among themselves, and some of them weren't really human at all!