Hi i hope you can help. The book i am looking for i first read in 1976, i cant remember the title or author. Almost everyone lives in one subterranean city, the story is about a tech who looks after the machines that farm the surface, he lives with a small group (family) in the lower levels of the city. There are primitives who live on the surface steal fruit and food from the gardens, if i remember the tech has to go out on the surface to repair machines at one point he is captured by a female primitive who forces him to mate with her. i think the primitives are hunted as a holiday pastime by some city dwellers. The story takes the tech and his group out onto the surface where they get better food become healthier, I hope someone can help me find this novel i have been looking for months for it.