[The inside-flap copy from Hc]: "Earth is offloading its surplus population as fast as the spacecraft will carry it away. Poorly prepared and equipped, the immigrants are landed on newly discovered planets and sent, protected by a token armed force, to colonise new and inhospitable lands. Swampworld West is such a planet, inhabited by strange but rational beings who live in comparative peace among the pioneers from earth, until some inexplicable urge for self-destruction creates havoc in the settlements and brings the constant fear of death to the pioneers."