John Perry did two things on his seventy-fifth birthday. First he visited his wife's grave. Then he joined the army.
The good news is that humanity finally made it to the stars. The bad news is that, out there, planets fit to live in are scarce -- and alien races willing to fight us for them are common. So, we fight. Far from Earth, the war has been going on for decades: brutal, bloody, unyielding.
Earth itself is a backwater. The bulk of our resources are in the hands of the Colonial Defense Forces, and everybody knows that when you reach retirement age, you can join up. The CDF doesn't want young people; they want people who carry the knowledge and skills of decades of living. You'll be taken off Earth, never to return. You'll service two years in combat. And if you survive, you'll be given a homestead of your own, on one of our hard-won planets.
John Perry is taking that deal. He thinks he knows what to expect. But the actual fight, light-years from home, is far, far harder than he can imagine -- and what he will become is far stranger.
I finally picked this book up recently after hearing about it several times. Some compared it to "Starship Troopers" which I have not read (only seen the movie unfortunately). I also saw it compared to G.R.R. Martin's work - though I think that is more because of the fact fans are forever waiting for the next book in the saga more than because of the content. Personally it reminded me a bit of "Ender's Game". Not that it was just like it, but that feel of following someone from earth, through training and then into war and experiencing what makes up the future as you do.
I'll try to keep things fairly spoiler free as usual. The book is broke up into three parts. The first follows John on Earth as he makes the final step to join up, the second follows his training more-or-less, and the last when he actually enters the forever war they fight. Each section has it's own builds and arcs and combined with the first person style of writing this story moves along very quickly.
Plot wise, there is no giant book-length plot other than following John Perry's life. The book does build into an important battle for the Colonial Defense Forces at the end, but even that takes a sideline to what Perry experiences during that battle. Which worked fine for me, John Perry was very likable and it was easy to get into his head.
The technology in this book was introduced as the character learned of them -- in turn teaching the reader about them. Personally I think traveling through space is always one of the trickier parts of sci-fi and even though Scalzi's explanation of "skip-drive" technology made sense - it left me with a little disconnect about the story. It's odd hearing that every time they travel, they actually leave their current universe and go to an alternate one, never to see the old one again. It raises several questions for me about certain things in the story - but I just went with it. I think sci-fi tech is a lot like magic in that regard. And in making that comparison I would rate this book somewhat "magic heavy" -- the tech used is out there. Granted it should be for the story he is telling, but be prepared for a mix of high concept tech and some pretty cool stuff.
In the end the book is just about John Perry more than the technology or the war. The only thing that raised my eyebrows outside of the skip drive tech were a few big coincidences in the book - one huge one that the story moving forward hinged on. Like before I just went with it. The book was a really easy read, both in the way it kept good pace and John Perry being enjoyable to follow. I just kept reading and told myself these coincidences were what made John Perry worth following story-wise.
I mentioned above some similarities to other books I've heard about. The only one I can say personally is that I think if you have tried "Ender's Game" you'll like "Old Man's War". But this is one of those books that no matter what genre you read I think you could pick it up and enjoy it. I'd highly recommend giving it a try if you haven't already.