To understand 20th Century warfare you must study the Battle of Stalingrad, the absolute deathstruggle of the worst of totalitarianism. Read “Life and Fate” by Vassily Grossman. He was a Red Army News reporter during the war and followed the Red Army all the way to Berlin. After the War the KGB attempted to confiscate all copies including typewriter ribbons of this book. This, because he was the first to equate Hitler and Stalin as co-equal Demons.
One of the main characters is a particle physicist; much of the book deals with his theories and how the Party Apparatus attempts to suppress him. It is chilling.
Better yet, back in the early '60s our NCO Club had a personal description of this from a former sergeant of the Wehrmacht who was captured there, survived a march/transport of prisoners to Siberia, escaped, and got back to the lines using "skis" made of wooden barrel staves. He had pictures of the invasion of Poland, and of the battle of Stalingrad. His description was horrifying, but professional. He was a really nice guy and gave the very impressive demeanor of a soldier who has been through it all, and still tough.