In German the title of this novel is Im Westen nichts Neues, which translates to In the West Nothing New.
The historical foreword to the book by Harry Hansen details the historical events, citing newsreel posts from Germany and France as the war ground along. To calm the masses, a regular refrain from the journalist community – co-opted by government naysayers – was that "all was quiet."
The words of this title appear in the final moment of the novel. Our protagonist dies when things are quiet. He survives many loud and chaotic battles, but dies on a day that is "all quiet."