Halo: The Thursday War

Halo: The Thursday War is the second novel in the Kilo-Five Trilogy by Karen Traviss.

Official summary
"Halo: The Thursday War picks up immediately where Halo: Glasslands left off, with forces on Earth and among the Covenant threatening a peace that is precarious at best. With a splinter group among the Sangheili pushing for war, some human colonies rebel against Earth authority; and as ONI policy continues to shift with the volatile situation in space, the discovery of a trove of Forerunner technology on Onyx provokes leaders on Earth to seek uses for it in the conflict. For the fight is far from over..."