Certainly, some of the best fiction to be written about the War comes from men who were there, who fought in the battles, experienced first-hand what they wrote about and based their *fiction* on the realities they knew.
Foremost we have to mention James Jones, whose books express the gritty, not so-pretty side of war and military life. Tough prose that rings in the mind and sets the heart to saying "Yeah, that's right. That's how it is."
The Thin Red Line
From Here to Eternity
"I also learned that in spite of all the training you get and precautions
you take to keep yourself alive, its largely a matter of luck that decided
whether or not you get killed. It doesn't make any difference who you are,
how tough you are, how nice a guy you might be, or how much you may know,
if you happen to be at a certain spot at a certain time, you get it.
"Men
had come from the Dayrooms to the porches to listen in the darkness, feeling
the sudden choking kinship bred of fear that supersedes all personal tastes.
They stood in the darkness of the porches, listening, feeling suddenly
very near the man beside them, who also was a soldier, who also must die."
----From Here to Eternity
"They had left all of their weapons platoon back with Colonel Tall
except for one machinegun. Stein had placed it on the extreme left
flank of the 3rd Platoon in the first line with orders to fire when they
heard him blow four short blasts on his whistle. Now, with his lungs
crammed full of air, his mouth open, his head pushed back and his whistle
moving to his mouth, he heard the MG open up, anticipating him." ---
The Thin Red Line
James Jones 1921 - 1977
--James Jones, letter to his brother, Jeff Jones, from Guadalcanal, January
28, 1943