I've just finished Old Man's War, a first novel by journalist, nonfiction author, blogger (!) John Scalzi. I was absolutely blown away; it literally was one of those "you can't put it down" books. I started reading it at lunch and had to force myself to break away two hours later in order to get some work done.
Let me crib the plot summary:
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 aliens willing to fight for them are common. The universe, it turns out, is a hostile place. So: we fight. To defend Earth (a target for our new enemies, should we let them get close enough) and to stake our own claim to planetary real estate.
Far from Earth, the war has gone 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, which shields the home planet from too much knowledge of the situation. What's known to everybody is 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 your time 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.
Old Man's War is in the military science fiction genre, but rises far above the usual crapola of that genre (see, e.g., David Drake). Indeed, I would rank it right up there with Heinlein's Starship Troopers and Haldeman's Forever War. In tone, I suppose, it is closer to the latter than the former. Scalzi's tone suggests that he recognizes the necessity of fighting for the survival of the species (or whatever), while still deploring the stupidities of war. As Scalzi put it on his blog, in commenting on a reviewer (the ubiquitous Harriet Klausner) who claimed it was an anti-war novel:
I don't know that I subscribe wholly to the book being anti-war. I would say that it is anti-stupid, in that at least of a couple of people acting stupidly in the performance of war reap the consequences of their actions. This also happens to be my general opinion of war: Use only when absolutely necessary; try not to use stupidly or wantonly; be prepared for the consequences.
Like Haldeman, moreover, Scalzi makes you care about the characters in a way that Heinlein didn't bother with. Most of the major characters are eventually killed in action; each death pangs just a bit. All in all, if military sci-fi is even remotely your thing, you need to buy this book.