L. Ron Hubbard's Battlefield Earth.

This is the abridged audio book. Approximately 8 hours long and read by the late Roddy McDowall, this version of the story eliminates the Africa subplot of the full book and in doing so improves the pacing of the story tremendously. Why the script for this wasn't used as the basis for the horrid Battlefield Earth movie I cannot fathom.

From Wikipedia:
In the year 3000 AD, Earth has been ruled by an alien race, the Psychlos, for a millennium. Humanity has been reduced to a few scattered tribes in isolated parts of the world while the Psychlos strip the planet of its mineral wealth. Jonnie Goodboy Tyler, a member of one such tribe, lives in the shadow of the Rocky Mountains. He leaves his village to explore the lowlands and to disprove the superstitions long held by his people involving ancient gods and monsters. However, he is captured in the ruins of Denver by Terl, the Psychlo chief of security. The Psychlos, hairy 9-foot (2.7 m) high, 1000-pound sociopaths, originate from a planet with an atmosphere very different from that of earth. Their "breathe-gas" explodes on contact with even trace amounts of radioactive metals, such as uranium. From the very beginning, the reader learns that Terl has discovered a lode of gold up in the Rocky Mountains that he wants to get his hands on "off the company books" but is surrounded by uranium deposits that make Psychlo mining impossible. Terl captures Jonnie by accident while searching for "man-animals" to train to mine where he himself cannot.

After a time, Terl captures Jonnie's girlfriend and her little sister and uses the threat of their deaths to ensure cooperation from Jonnie. Jonnie is afterwards free to move around the mining area. Shortly thereafter, Terl and Jonnie travel to Scotland and recruit 83 Scottish youth to help with the mining. Jonnie, however, has different plans. Due to the fact that Terl does not understand English, Jonnie is able to convince the Scots to help him overthrow the Psychlo rule on Earth.

During the next several months, Jonnie and the Scots try to mine the gold as well as develop a means of defeating not only the Psychlos on Earth, but also nullify the threat of counterattack that could come from Psychlo (the Psychlos' home planet). During the semi-annual teleportation of personnel, goods, and coffins (all dead Psychlos are shipped home for burial on Psychlo) back to Psychlo, Jonnie and the Scots manage to pack several of the huge coffins with nuclear dirty bombs and "planet busters" in hopes of destroying the Psychlos' home planet. After the teleportation firing, the humans use the Psychlos' own war planes, tanks, and weapons against them and regain control of Earth.

This is, however, not the end of the story. Unsure as to whether the bombs sent even reached Psychlo and under the imminent threat of counterattack, Jonnie must now defend his newly-retaken planet against the predatory interests of several other interstellar races, including a race of intergalactic bankers seeking to repossess the Earth in lieu of unpaid debts, as well as a newly-emerging group of humans seeking to wrest control of Earth from him. In order to ensure the security and independence of Humanity, he does something that no other race in 300,000 years has been able to do: uncover the secret of Psychlo mathematics and teleportation.