The Thin Red Line by James Jones
There are many excellent reviews on Goodreads, from which much background to the author and the battles on Guadalcanal can be gleaned.
This is an ant’s-eye view of Armageddon. Jones was a veteran of WWII and his experiences show. The pervading mood is despair; where there isn’t, there is insanity. It is an anti-war book in the way that All Quiet on the Western Front is anti-war: the authors tell it like it was for the participants, and it was horrific.
There is nothing to suggest in today’s news that anything has changed for those caught up in war.
PS The book was first published in 1963, only eighteen years after WWII ended. I was five. I grew up in the shadows of that war without realising it: I thought it was ancient history. Now, I see the shadows.