The twentieth century may have been the first to be dreaded even before it arrived; for every imagined progressive force, there was an unequal and opposite reactionary force; almost overnight, the stage darkened. Some have argued, in fact, it had already begun in 1889, the year Nietzsche went mad and Hitler was born. Some sense of doom often precedes the dawn of a new century or millennium, but this time it seemed different, and it was: the new century would bring war, death, and genocide on a scale hitherto unimaginable; it would witness the despotism of Hitler, Stalin, Franco, Pol Pot, and Jorge Rafael Videla Redondo; it would see the emergence of nations from oppressive colonial regimes hurled into far worse ones; it would see the invention of the ultimate weapon of destruction: the nuclear bomb.
One could list a number of other things that were actually quite good about this century -- Penicillin, the Polio vaccine, manned travel to the Moon, the Civil Rights movements in the United States, and microwave popcorn -- but that would be beside the point. The fortunate are not always happy, nor are the poor necessarily miserable; the texture of lived experience owes something, but not everything, to its material conditions. Our feelings often cathect toward moments and symbols that seem to bring us together or tear us apart, and at these untimely interstices we are gathered for a moment, so that literature and the arts may take our picture.
There were a number of such moments in the early years of the twentieth century: one thinks of the funeral of Queen Victoria in 1901, the sinking of RMS Titanic in 1912, and the opening battles of WWI in 1914. In literary and cultural terms, there's the first issue of Wyndham Lewis's Blast!, the 1913 Armory Show, the serialization of Joyce's Portrait of the Artist as a Young Man in 1914-15, and the "Great War" itself, which permanently altered the careers of many writers, both those who survived (J.R.R. Tolkien, Robert Graves, Siegfried Sassoon) and those who didn't (Wilfred Owen, W.N. Hodgson, Rupert Brooke). And then there were those who survived physically, but were shattered, such as Ivor Gurney.