I'd like to nominate The Great War and Modern Memory
, Paul Fussell's seminal study of World War One as the dawn of the modern era, using the the narratives of British memoirists and poets as the prism with which to view it. Fussell pinpoints accounts which were both historical experience and artistic rendering, with the overarching leitmotif of tragedy.
The book, published in 1975, won both the National Book Award and the National Book Critics Circle Award. I think it's especially relevant as we approach the one hundredth anniversary of the start of the Great War, as we see how much the world has changed and to what extent the world hasn't learned the excruciating lessons of that conflict.