Remarque highlights how the patriotism once linked to war has become outdated as new recruits quickly encounter the grim realities of trench warfare. At the novel's start, Paul Baumer, fresh from school, undergoes a short yet harsh basic training before being dispatched to the trenches in France. He soon discovers that survival relies less on a soldier's expertise and more on their automatic responses. With the Allies possessing superior artillery and machinery, the German youth sought shelter in trenches that were ill-suited for the warfare they encountered. As Baumer witnesses the increasing deaths of his comrades, he realizes that death often comes from distant artillery shells and bombs. The trenches provide decreasing protection against the enemy's advanced tanks, airplanes, and superior weaponry, making survival largely a matter of luck.

The main theme of All Quiet on the Western Front is the individual's battle against uncontrollable forces like technology, institutions, politics, societal norms, illness, and death. The soldiers transform into automatons, concentrating more on dodging death than on fighting. The narrative rapidly shifts between locations: the front lines, where soldiers take shelter from shelling in a cemetery, endure gas attacks, and spend time away from the front; home leave in a Germany unable to comprehend the front-line reality; interactions with Russian POWs; and hospitals, where the war's harsh impacts are most visible. The increasingly condensed final chapters depict the young German troops' defeat, unable to compete with the more energetic, better-nourished Allied forces. Baumer's death occurs just before the armistice, portrayed as scarcely noteworthy.

The omnipresent atmosphere of death, Muller's indifferent request for Kemmerich's boots, the theft of his watch, and a soldier's willingness to trade cigarettes for morphine to aid a dying comrade emphasize the theme of the absurdity of modern life, where humans must grapple with impersonal mechanistic forces.