I finished this tonight; just a few random observations.
World War I produced some of the best war novels -- or more precisely antiwar novels -- I think because it was not only one of the most horrible wars in history, with the trench warfare, but one of the most senseless, and the soldiers soon understood that. The passage after the Kaiser's visit when they discuss what they are fighting for, and who was responsible for the war, I think is key: none of them can really figure it out, none of them thinks they are fighting for anything worthwhile, they say they are fighting to defend their country but then recognize that the French are fighting to defend their country as well. There was really nothing to choose between the two sides; the English and French propaganda said they were fighting against "German militarism", but they were fighting on the same side as Czarist Russia, which was far less democratic than Germany or Austria even under the Kaisers. It was almost transparently a war for markets and colonies; it's no accident that it resulted in a revolution in Russia and an unsuccessful one in Germany.
Comparing World War I with World War II, in the later war there was much more feeling of fighting for something; the Germans had real grievances for their treatment after Versailles, and mostly believed in Hitler's ideology, while of course -- whatever the real aims of the allied governments -- the allied soldiers considered that they were fighting against the very real evil of Naziism. This is why, in my opinion, the literature from World War II is much more superficial, more "heroic" and "patriotic" in tone; in fact most of the good literature from or about the period of WW2 deals with the Holocaust rather than with the war per se. I interrupted my reading of Doris Lessing's autobiography to read this in time for the discussion; but the first chapter of that talks about the effects of WW1, which she claims, I think rightly, shaped the twentieth century -- she describes going to France in 1992 and looking at the War monuments in the small villages, and reports that in each village there is a list of twenty or thirty names from WW1, sometimes all the young men of a village, and on the other side, one or two names from WW2. Of course, WW2 had about four times the number of dead as WW1 (ca. 40 million vs. 10 million), but it was fought all around the world, where WW1 was concentrated in Europe, and with a smaller population. She also points out, what I had never realized, that in the year after the armistice, about 30 million people died of famine and epidemics, especially influenza, so the total was about the same as WW2.
I think this is one important aspect of the novel to point out, that while it is "about" the war and ends just before the Armistice, in a sense it is also about the results: the beginning epigraph talks about a whole generation destroyed, even if they did not die in the trenches, and throughout the book there is an emphasis on how the soldiers will not fit in after the peace, about how they are permanently changed and psychologically maimed. There is also the constant discussion of disillusionment and betrayal. The effects of WW1 were long lasting, and in a real sense the rise of Hitler and thus WW2 were a direct result of WW1.
Both my grandfathers fought in WW1, and both were gassed; one mostly recovered (although he eventually died of lung disease) but the other was a permanent invalid. I remember him always sitting in his rocking chair, obviously weak and sick, not really talking to anyone, and always in and out of the VA hospital. (Ironically, he had been an athlete, who just before the war was about to be signed by the NY Yankees.) Again I return to the Lessing autobiography, and the semiautobiographical Children of Violence series that I just finished rereading, because Lessing's father, and the father of the main character in the novels, reminded me so much of my grandfather -- both the real and fictional fathers were always ill, never really related to anyone, were obsessed by their war experiences, etc. I think this is true of many of the returned veterans of that war. On the other hand, my father and his brothers, and my other uncles, who all fought in WW2, never talked about it much, seemed to forget it and get on with their lives. Vietnam perhaps is a closer analogy to WW1, except that the Vietnam vets were a much smaller percentage of the population.