This is book 5 of the 6 that Campbell plans for this series. The entire series is fast moving, believable, and absorbing.
In Relentless the action slows a bit as the lost fleet has almost reached the safety of home space, but not quite. The ships of Black Jack's fleet are damaged and running low on supplies and there is still a battle ahead of them before they can get home.
Mr. Campbell has vividly imagined space warfare with its unimaginable speed and the frustrating delays. You can truly get the feel of what it would be like.
Character development takes a back seat to action here, but I have grown quite fond of Captain Geary and his companions. I can't wait for the 6th and final book to come out.
If you have not read the other books, I would not advise starting with this one. But it is an enthralling series. If this book interests you, consider starting with first book and working your way through to Relentless. You will have a great time.
Although the premise of the book seems unnecessarily silly (a spacer who is recovered from an escape capsule 100 years after his ship blows up) it did not distract me from what was otherwise a fun romp through space. I enjoyed the author's character development and action scenes (I guess you can have "scenes" in a book??). I was mildly put off by some of the compassionate preaching, but then I subscribe to the "Kill them all and let God sort them out" philosophy. If you like space combat novels then you will like this one.