Here's a fun book for you. Space travel, time-dilation, the cyclical nature of social norms (and the Overton Window), the futility of war... And, of course, science fiction's favorite pastime--predicting the future. There's a very humorous thought about microfiche in the middle of the book. ;) 
 I'll go easy on the accolades, because I really don't think I can do this book justice. The writing is spartan in nature, but it fits the voice of the protagonist. The themes, though well-explored today, are still resonant. Yes, it's about Vietnam--but it's also about any war, any time, any place, and that's something worth reading about. 
 Of course, there are some parts of the book that haven't aged terribly well. What was revolutionary in the seventies can seem downright conservative in 2015--but that's the nature of the Overton Window for you. 
 I was going to wait to finish reviewing this, but I thought I'd go ahead and jot down my thoughts while they're fresh. I look forward to comparing this to Starship Troopers and Old Man's War, both of which are in my current reading list.