S.D. McKee, Defeated

Defeated by S.D. McKee is set in a gritty future, and deals with mankind's first attempt to venture into deep space via Operation Giant Leap; a wormhole experiment that leads to a surprisingly disastrous outcome. Once hopeful of colonizing a distant world, the human fleet, led by Captain Jonathon Quinn of the ICS Intimidator, finds itself plunged into a war they didn't want and have little chance of winning. Much of the story is difficult to explain without spoiling the twists, but suffice to say, Captain Quinn and his crew are faced with difficult decisions regarding how to defeat an ancient and powerful enemy that is bent on destroying the human race.

The pacing of the book is appropriate for a military sf novel, and the action and tactics are well described. Though Defeated could stand on its own, it's actually the first book a new series title, "Darkness Among the Stars."