"Antiwar novella concerning a German foot soldier in World War I, horribly wounded and baled up with the other battle casualties to be rendered into soap. After this, things really get strange. Owen is best known for More Things in Heaven."
#10 on KEW's 13 Best Science Fiction Horror Novels list is The Cross of Carl by Walter Owen. The subtitle of the book is:
"An allegory; the story of one who went down into the depths and was buried; who doubting much, yet at the last lifted up his eyes unto the hills and rose again and was transfigured".
This may be the shortest work on the lists. It can easily be read in one sitting and looks to have been originally published in the form of a tract. I'm not exactly sure how it was first published since I've read it in the Groff Conklin 1951 collection In the Grip of Terror. I would describe it a novella due to it's brevity.
Cross is the story of Carl, a nondescript older recruit in a pointless war, which seems modeled after WW1. Desiring to win the "Cross", Carl becomes involved in an assault from the trenches on "Hill 51". The first section of this piece is a gruesome description of trench warfare (before air support changed everything). Troopers in tunics and gas masks attempt to over-whelm an enemy position fortified with snipers. Carl watches his comrades ripped apart by bullets and shells until he himself is dispatched in a mine explosion. The account of the battle is detailed, with body parts flying all over the place.
But the second part, "Golgotha", is even worse as Carl finds himself thrown into a train of bodies bound for the Utilization Factory of the Tenth Army Division. In essence, this is rendering plant to dispose of war dead. Corpses gleamed from the battle fields are sent to this plant to be processed into pig food and fertilizer. Carl is tossed in with the rest of the corpses, but he's not dead, merely unconscious. When he wakes up amidst the bundles of bound bodies destined to be processed, he goes insane.
The conclusion of the book has Carl wondering around a swamp preaching to any and everything he encounters. Finally, Carl encounters the army officers who sent him to the front. The ending is hideous, which is why some people have christened this the best anti-war narrative ever written.