Discussed in this essay:

Iron Curtain: The Crushing of Eastern Europe, 1944–1956, by Anne Applebaum. Doubleday. 608 pages. $35.

One of the twentieth century’s most significant innovations was the concept of world war, and it managed to stage not one but two, as if the first weren’t good enough and had to be perfected. Figures for the death toll in these wars vary widely, but whereas World War I (“the war to end all wars”) notched up something like 20 million deaths, World War II (“the greatest man-made disaster in history,” according to Antony Beevor in his new…