I did two things on my seventy-fifth birthday. I visited my wife’s grave. Then I joined the army.
Visiting Kathy’s grave was the less dramatic of the two.

In a distant future, humanity developed, colonized different worlds and fights wars. The protagonist joins the Colonial Defense at 75 years old and finds that his conscience is transplanted in a new, young, augmented body. With that, he regains practically a second life, but the war he is about to embark and the Colonial Defense are a lot more sinister and mysterious than he thought.

This book is a classical military sci, with an engaging premise and a good follow up. The ending is a bit open, more scifi than military. Overall, the book tilts towards a mystery scifi rather a military story.

Most of the book follows the transformations, physical and psychological, of the hero, John Perry, after the body transplant. After the training camp, the protagonist fight various aliens, gradually climbing ranks.

It was a good book, but not exceptional. Nonetheless, entertaining enough to finish it, but no continue with the series.