I will pick a few books with the same theme, one that I really love: that of a genetically engineers/modified soldier.
Armor by John Steakley.
The Cobra Trilogy by Timothy Zahn.
Blackcollar by Timothy Zahn.
Old Man's War by John Scalzi. First in a series.
I'd recommend any of them but I love Blackcollar the most.
Also I'm sure I missed more than a few. Would love to find them out.