The Forever War

This is obviously a classic in the realms of sci-fi and of anti-war novels, and another book with thousands of reviews that I can't improve upon, but I'll just offer a couple of insights.

One of the primary concepts from the book is the main character returning from space travel (complete with Spacial Relativity) to an Earth that was completely foreign to him; it was a massive dose of culture shock which progressed deeper and deeper the further the story went. I was in the US Air Force for 22 years, and can say without a doubt that returning to the US after a 4-year overseas assignment to the Philippines, that this type culture shock is a real thing. I was stationed there from 1985-1989, and basically immersed myself in the Philippine culture. When I returned to the US in mid-summer 1989, there was so much that had changed in 4 "short" years. Imagine being a military member sent to outer space, traveling through colapsars (wormholes), and returning to Earth a century or more in the future while you've only aged a few weeks or months.

The other thing that the author captures very well is the lack of understanding of the "big picture" at the lowest enlisted level. This is something that will always be a factor in any military, even though you constantly hear, "think of the military objective". That objective is so obscure and far-off that the peons have no idea why they do what they do. They follow the propaganda that the enemy is "evil", and that our government is "good". This was Haldeman's view of the Vietnam War in a nutshell. His allegories, especially early on, with the battalions attacking Tauran "villages" were spot on, and the question of whether the troops destroying said villages as part of the overall military objective was something our troops continually struggled with, coming home with PTSD. He didn't mention it in the story, but you can see the effects of PTSD in a lot of the characters in the book.