What is Reddit's opinion of Achilles in Vietnam: Combat Trauma and the Undoing of Character?

From 3.5 billion Reddit comments

I really, really recommend Achilles in Vietnam if you're interested in this stuff. A little bit dated now, but to me it was really eye-opening in how it approached PTSD, especially with how it connected the Vietnam-era soldier with the hero of The Iliad, Achilles. But the common thread that seems to crop up isn't that PTSD is primarily caused by people killing enemy combatants. The act of killing isn't necessarily the traumatic part. It's the amount of active combat that modern soldiers are a part of continuously, and the betrayal of accepted expectations of how war goes or is supposed to go. Even professional soldiers in the medieval time would spend much of their soldiering on campaign on the march, traveling, posturing, setting up for battle and then - if battle was refused - marching again. It was still hard and shitty, and sieges were godawful, but it wasn't continuously being attacked or having the potential to be attacked by enemy combatants. They weren't lying awake every night wondering if a bomb or an artillery shell or a bullet would get them the next day. Guilt and regret definitely have their place in the minds and hearts of returning soldiers, but for PTSD it seems more to be about - for many men and women, anyway - that there's a hypersensitivity that turns on in active combat that doesn't get turned off back home, etc.

The Crusades are interesting, as the crusaders were in enemy territory for the most part... But they had conquered parts of the Holy Land to shack up in, with fortified castles and cities, and those fortified areas were (largely) secure. There's a book... can't remember what it's called, but it's a written account by an Arab nobleman of his stupidly crazy adventures during this period, and at times he mentions the crusading Europeans - who he always laughs off as timid, unwilling to really commit to battle unless ambushed or surprised.

https://www.amazon.com/dp/B003L77XA4/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1

Achilles in Vietnam was the first book he did on the subject.