Old Man's War, by John Scalzi
I read both science fiction and fantasy, but the truth is that the fantasy in my reading list outstrips its technological brother by about twenty to one. I've got nothing against SF, but I'm only sporadically in the mood for it, and then only for certain kinds. (Idea-driven SF is not for me, not unless it also has really good character development, and few authors can manage both at once.) So on the day that I picked up Old Man's War, I was more taking a look at it than sitting down to read it.
I finished it that same day.
Which tells you both that it's a quick read, and a fun one. All I really knew of OMW before picking it up was that people were comparing it to Heinlein, and for me, that's not necessarily a recommendation. I haven't read much Heinlein at all, but I'm generally much more on board with modern SF, not old-school stuff. Scalzi, however, got the best of Heinlein and none of the worst, at least as I define those qualities. The result is the type of SF that is packed with Nifty Ideas and makes a nod toward technological plausibility but doesn't stop to explain it all to you; it's too busy with plot and engaging characters. In other words, my kind of SF exactly.
I'll only talk about the opening premise, because one of the hooks the book sinks into you in the first few pages is that you don't know what's in store. Earth is under a kind of quarantine, with off-planet travel strictly controlled. There are only two ways off this rock: if you're from a Third World country, you can become a colonist, or if you're from a First World country, you can wait until you're seventy-five and then join the army.
Even the characters don't know why the Colonial Defense Force only recruits geriatrics. That isn't in the recruitment spiel. They have guesses, of course, but they have to jump blind; if they even make it to seventy-five (since life expectancy isn't that much better than it is now), then they have to either stay home and croak of old age, or sign on the dotted line and only after getting off planet find out what they signed up for. (Nor, for that matter, do they know why they can't be colonists, and Third World citizens can. The colonial government doesn't tell people much of anything.)
What they do know is that it's a vicious universe out there, and the CDF needs soldiers to protect their colonies. So while I won't tell you why the army is made up of old men (and women), nor what happens to them after their recruitment, I can say that this is rollicking military SF packed with gosh-wow conceits, and that yes, there are problems with rollicking military SF, if you're of a liberal and/or pacifist bent. Scalzi himself is not the conservative some readers apparently assume based on this book, and I might add that the sequel The Ghost Brigades does a nice job of saying "you know that thing that bugged you? Yeah, it should bug you." I haven't read the later books, but I hope that trend continues. To pick just one example, you finally get an explanation for the colonist/army recruitment divide, and it is both interesting and something you could easily argue with. Definitely keep in mind that just because an author puts something into his story doesn't mean he thinks it's a good idea. He just thinks he can tell interesting stories about it.
Ultimately, I think I liked this book (and the sequel) because it's damn funny, without being humorous SF as such. John Perry is a likeable protagnist with a sense of humour I can get behind, and the technology contains a lot of fresh-to-me ideas that are painfully appropriate extrapolations of current developments. (The FTL travel I could care less about -- it's a new paint job on an old trope; whatever -- but the BrainPal leads to some hilarious scenes.) So this isn't meaty thinky SF, but it has a sense of fun, and that's generally what I'm looking for anyway.