Joe Haldeman’s The Forever War is probably the most highly regarded military sf novel. It begins a lot like Starship Troopers. A young man from Earth, William Mandella, is drafted to fight an alien menace. He goes off to boot camp, which is highly dangerous, and, as in Heinlein’s novel, includes powered armor. Then, he and his unit deploy to a distant planet to fight the strange aliens.
There are a couple of twists after this opening sequence that do differentiate the novel from Heinlein’s, however. First of all, it’s pretty clear that not all is as it seems. Rather than the simplistic aggressive force that Heinlein’s “bugs” represented, Haldeman’s aliens are more complex and mysterious. In fact, it’s not entirely clear why Earth is at war with them. And, rather than the heroic patriotism of the space marines, Mandella and his fellow soldiers are miserable, occasionally cowardly, fight amongst themselves, and regret killing. In other words, it’s an anti-war military sf novel. It’s not surprising that this novel was written in the wake of the Vietnam War, or that Haldeman served in Vietnam.
From what I’d heard of this novel, I thought the anti-war message was really the novel’s focus. It’s actually subtler than I expected, and there are times when this does read like a typical military adventure story. The main twist and the real focus of the plot is the fact that Earth’s fighting forces are subject to relativity. As established by Albert Einstein, if you travel near the speed of light, time moves much more slowly to you relative to the stationary position you left. Thus, when the infantry deploys to their first alien planet (aided by shortcuts through space called “stargates”), the mission takes several months for them, but twenty years pass on Earth. As a result, a lot of the novel involves Mandella and his fellow soldiers adjusting to massive changes in society every time they make it back from a mission.
The first mission begins in 1997 (The Forever War may be the champion of bad futurism, placing interstellar travel and power-armored space infantry just years away from his mid-70s vantage point). Then we get the standard-70s dystopia in 2007: overpopulation, starvation, pollution, etc. From there, we learn of big changes in world governance, population, and, most dramatically, human sexuality, as the centuries fly quickly by.
I’m not a fan of military sf, so the long training and combat scenes, which make up more than half of the novel, could be a bit of a slog, and I’m not quite sure that this book lived up to the hype. But it was an enjoyable read with some entertaining ideas thrown around.