Title: Robotech Genesis (#1) (Robotech)
Description: From the back cover:

ABANDONED ALIEN BATTLE FORTRESS!

It saved humanity from itself, but there was a price: hot on its trail came the most merciless enemy of all!

The Global Civil War was about to make Humankind extinct, when the stupendous Super Dimensional Fortress dispatched to Earth by a dying alien genius changed all that forever, and altered the history of the universe.

Humanity's only hope lay in a corps of untried, resolute young men and women: the Robotech Defense Force.

They were entrusted with powers they didn't fully understand.  Then the most feared conquerors in the universe attacked, determined to destroy them for no reason they could comprehend.

The war began as... A UNIVERSE HUNG IN THE BALANCE!
Subjects: Space warfare, Fiction