Deathworld 2

Deathworld 2 is the story of The Ethical Engineer, written by Harry Harrison and first published in 1963. Jason is kidnapped by a self-righteous enemy out to bring him to justice for his various crimes. He forces a crash-landing on a planet where the human population has regressed. The technology is extremely primitive and knowledge is split up among many small clans, each one jealously monopolizing what it knows. Jason uses his ingenuity to survive, trading his knowledge for protection and power in one of these clans. He constructs a device that is a primitive communication device in disguise; it eventually signals his location to a spaceship piloted by his Pyrran girlfriend, Meta.