The Forever War by Joe Haldeman

I can see why this book was a highly praised classic. It’s a good book that skirts the edges of hard sci-fi, particularly with concerns like relativity. It’s a great soldier’s eye view of the world–though the details are sometimes a little shortcut, it makes the book a compact and powerful read.

There’s some very nice sleight of hand with society and its changes in the background, allowing only the nearest future to be clearly defined, but the remainder to give a strong impression.