If you like your science fiction techno action with a healthy dose of Vietnam-era nihilistic futility, The Forever War is the book for you.
Originally published in 1974, it tells the story of a man, conscripted into a future Earth army, who is sent to the farthest reaches of the galaxy to fight a mysterious alien enemy. Thing is, since he’s traveling to battle at near the speed of light, while he’s gone on a one-year mission, the people back on Earth are aging 20 or 50 or 100 years. After every deployment, he comes back to an Earth that’s like an alien planet to him (like I said, Vietnam-era).
Some of the military descriptions don’t ring true anymore. The use of draftees seems wrong now that we’ve seen the capabilities of a professional, all-volunteer military. And something like 10-12% of the conscripts are killed in training — losses that no competent modern military would stand for.
But it’s an interesting concept, told with a compelling level of detail. You feel how difficult it would be to perform military maneuvers on a planet where hydrogen freezes on a typical balmy summer afternoon. You feel the danger and claustrophobia of being sealed into a pressure tank for weeks at a time so your body can withstand the rigors of interstellar travel.
Interwoven throughout, there’s also lots of subtextual commentary about the horrors of war, man’s inhumanity to man, xenophobia, sexuality, etc., etc. Again, it’s science fiction with a Deer Hunter spin. If that’s your thing, then this is your thing.