Battlefield Earth

Battlefield Earth is a science fiction novel by the American writer L. Ron Hubbard, published in 1982 and subtitled A Saga of the Year 3000.

The Earth of the novel is a mining site: the Psychlos are nine feet tall, breathe a gas that explodes on contact with uranium, and have been the dominant species of several universes for at least a hundred thousand years, which is why nobody expects the humans to be able to refuse them anything. Jonnie Goodboy Tyler is a young man from a tribe near the ruins of Denver who goes down into the lowlands to prove to himself that the monsters his people fear are real. He is taken by Terl, the Psychlos' chief of mine-site security, who has just learned that his tour on Earth has been extended and who wants a fortune in Rocky Mountain gold badly enough to break the rules to get it. Since the gold sits among uranium deposits that the Psychlos cannot go near, Terl needs human labour, and Jonnie becomes the means of finding it, learning the Psychlos' language and their machinery as he goes, and eventually meeting a group of Scots who can help him use what he has learned. Hubbard also composed a soundtrack for the book, and in 2000 it was adapted into a film.