In the evolution of every sentient race, there is a turning point when the species achieves transcendence through technology. The warlike Sh’daar are determined that this monumental milestone will never be achieved by the creatures known as human. On the far side of known human space, the Marines are under siege, battling the relentless servant races of the Sh’daar aggressor. With a task force stripped to the bone and the Terran Confederation of States racked by dissent, rogue Admiral Alexander Koenig must make the momentous decision that will seal his fate and the fate of humankind. A strong defensive posture is futile, so Koenig will seize the initiative and turn the gargantuan Star Carrier “America” toward the unknown. For the element of surprise is the only hope of stalling the Sh’daar assault on Earth’s solar system-and the war for humankind’s survival must be taken directly to the enemy.
Center of Gravity is the second book of Ian Douglas in the Star Carrier series. The story revolves around the struggle of humanity to battle technologically superior races of allies, in distant future. The main protagonists are Commander Koenig, admiral of a human fleet, and Trevor Grey, pilot on one of the ships from Koenig’s command group.

Koenig allows the reader to see things at the strategic level, why the fleet retreats or attacks and the overall plan. Grey’s narrative level is more emotional and tactical, about simple people and how the war affects them.
The main ship of Koenig’s command group is kind of a spaceship carrier, where Grey’s spaceship is allotted to, hence the name of the series, Star Carrier.
Humans battle an alien species called Sh’daar which fight through various other alien species under their control. In the first book, the aliens attacked Earth and humans barely succeeded to repulse the attack, through the efforts of Grey and Koenig.
In the second book, humans strike back, The pace is fast and the star battles and the ship to ship action are dynamic and engaging. While not as innovative in new technologies and ideas as the first book, the story still reads well. Overall, it is a good piece of military scifi.
Link to Book 1 review.