Science fiction is still young. Perhaps it's eternally young. Optimism, bull-headedness, and a gung-ho attitude never seem far away when one foot is always in the future. But the genre is also old enough to have set a number of precedents, to have in living reader's active recall the memories of first reading the first books where a genre standard was created. Those memories are what keep many readers searching through the shelves to find something that truly re-invents the trope rather than simply recycling it. A huge number of today's science fiction readers and writers first encountered the genre when they read Robert A. Heinlein's juvenile science fiction novels, regarded by many as his best work. In those books, Heinlein invented many a standard, and they've been revisited by many a writer. Still, it's tough to imagine how one might go about re-creating the adolescent joy of reading a science fiction novel for a jaded adult who has spent a good part of the last century and all of this one reading them.

'Old Man's War' by John Scalzi manages to set a particularly difficult but specific goal for itself and then achieves the goal with the kind of reckless ease exhibited by its hero, John Perry. John Scalzi has done no less than write an adult version of a Heinlein-juvenile-styled novel for the adults who grew up reading Heinlein's originals. While the book is aimed at an mature audience it provides those that audience the warm thrills they experienced some twenty-thirty-forty-fifty-sixty-seventy years ago when they first read science fiction. But Scalzi's success is not just nostalgia. He's written a thoroughly entertaining addition to the science fiction canon of Space Adventures with a few original twists.

As 'Old Man's War' begins, more than a couple of centuries from now, humanity has made it out into space. We're not alone and we're not welcome. There aren't that many planets worth colonizing, and there are lots of aggressive, intelligent species trying to do so. We've got to fight for our right to party. John Perry is seventy-five. His wife is dead and he has little to look forward to except more aches, more pains and the slow descent into old age. So, like many his age, he joins the Colonial Defense Forces. And wham-bam-thank-you-ma'am (the officer at the recruitment desk is in fact a woman), he's in the Army now.

From there onwards, Scalzi piles on the fun and cops an attitude that lasts for the entire novel. Mordant, occasionally laugh-lout-loud funny, 'Old Man's War' sets up the rules and then plays by them. I'm not going to tell you how Scalzi gets around the aging issue, but I will tell you that he does. It's a pretty clever trick, but it does allow him to avoid dealing with the physical issues of growing old. Suffice it to say that the old folks you see on the cover don't last for more than 75 pages. But they bring with them a wealth of experience that occasionally helps them overcome the series of hurdles that Scalzi sets up.

Scalzi does all sorts of stuff right in this novel. He gives his grunts a damn fine gun. He gives them some nice new software that allows them to communicate with one another, and in a sort of tribute to Thomas M. Disch's classic story 'Fun With Your New Head' includes a pamphlet that tells the recruits how to have fun with their...but that would be telling. Suffice it to say it's a neat piece of satire. He also gives them a BrainPal and a few nice nods to the cyberpunks, then it's off to war. The battles build cumulatively to a final grudge match that involves brains, brawn and a bit of derring-do.

Written from the first-person point-of-view of John Perry, Scalzi's prose is serviceably slick and often funny. But he doesn't go overboard. There's a nicely meat-and-potatoes feel to this novel, which is perfectly appropriate to the subject and the effect that Scalzi successfully generates. Strangely enough, though this is a novel of space adventure, there's not too much rocket science here. There is enough to get us out in space and few nice speculative touches to keep you thinking. But this is not a book of big thinks.

Since this is a book about fighting aliens for planets, readers can expect the aliens to come early and often. That is the case, and there are some pretty imaginative spins on extraterrestrial life. Still, you won't exactly get detailed monsters here; you got your green slime, your big lobster, your monster dogs, and even some monster deer. The monsters however, are not the point, the people are.

Scalzi's universe and his literary format lend themselves to an episodic style. He'll create one set of characters for John and then systematically kill them off. If John Perry weren't such a strong presence the novel might seem disjointed, but Scalzi holds things together pretty well. He does some excellent hint-dropping to set up what proves the be the main thrust of the novel and ties things up rather nicely, leaving room for the sequel he says is already in the works, 'The Ghost Brigades'.

'Old Man's War' is not just an old man's novel, though it will hold strong appeal to those of us who first cut their teeth on 'Have Spacesuit Will Travel' and especially 'Starship Troopers'. Readers new to the genre, and indeed women will find it rather more appealing than they might at first suspect. Scalzi knows a lot of things, something he makes clear in the course of the novel. But he knows one thing vital to the novel's success. He knows how to have fun.