Old Man's War by John Scalzi

John Perry did two things on his 75th birthday. First he visited his wife's grave. Then he joined the army.
The good news is that humanity finally made it into interstellar space. The bad news is that planets fit to live on are scarce--and alien races willing to fight us for them are common. So: we fight. To defend Earth, and to stake our own claim to planetary real estate. Far from Earth, the war has been going on for decades: brutal, bloody, unyielding.
Earth itself is a backwater. The bulk of humanity's resources are in the hands of the Colonial Defense Force. Everybody knows that when you reach retirement age, you can join the CDF. They don't want young people; they want people who carry the knowledge and skills of decades of living. You'll be taken off Earth and never allowed to return. You'll serve two years at the front. And if you survive, you'll be given a generous homestead stake of your own, on one of our hard-won colony planets.
John Perry is taking that deal. He has only the vaguest idea what to expect. Because the actual fight, light-years from home, is far, far harder than he can imagine--and what he will become is far stranger.  From Goodreads.

This book was nothing like I expected. I expected a book about a war and it is about war on lots of fronts with blood and gore but it is also about human nature and friendship. Old people joining up for something they know nothing about, they just think someone knows how to make them younger.
I didn't actually know this was the first book of a series when I read this but it is and I am definitely looking to read more of John Scalzi's books.

This book qualifies for:
100 books in a year Reading Challenge 2012, 
Goodreads 2012 Reading Challenge,
2012 Sci-Fi Challenge,
2012 Ebook Challenge,
Scavenger Hunt 2012 Reading Challeng