In February, the last surviving American veteran of the First World War died. It is hard to imagine the day when we say goodbye to the last survivor of the Second World War, so large do the “good war” and the “greatest generation” still loom in the national imagination. But the calendar and the census do not lie. Some 16 million Americans served in the military during World War II. On the 60th anniversary of the attack on Pearl Harbor in 2001, about 5.5 million were still living. This year, as we prepare to mark the 70th anniversary, the number is closer to 1.5 million, and it drops by almost a thousand a day....

Americans’ favorite World War II stories have always been about the democratic heroism of ordinary soldiers; this kind of popular history has never disappeared, and probably never will. Laura Hillenbrand’s “Unbroken” (2010), which has resided for months near the top of the best-seller list, tells the story of Louis Zamperini, an ex-track star turned airman, who was shot down over the Pacific and survived weeks adrift on a raft and even worse ordeals in a Japanese prison camp. As the title suggests, Zamperini is an untroubling kind of war hero, because his greatness was his refusal to break, not his ability to break others — a part of the soldier’s job that is far less comfortable to read about. Zamperini was a bombardier on a B-24, and at the very time he was being tortured by the Japanese, other bomber crews, made up of men no better or worse than he, carried out “Operation Gomorrah” — the weeklong raid on Hamburg, Germany, that in July 1943 killed some 40,000 civilians and destroyed virtually the entire city. Can we make room for that story, and others like it, in our memory of World War II? And if we do, can we still keep our pride in a “good war”?

Those are the questions being asked by the new wave of World War II histories. These books are not “revisionist,” in the pejorative sense: they don’t suggest a moral equivalence between the Axis and the Allies, or minimize Nazi crimes, or deny the Holocaust. Rather, they are thoughtful works by professional historians, who are less interested in rewriting the facts of the war than in reconsidering their moral implications. Americans who learn about the war in Europe from a book like Stephen Ambrose’s “Band of Brothers” (1992), for instance, could be forgiven for thinking of the defeat of Germany as the work of doughty G.I.’s. Yet in “No Simple Victory: World War II in Europe, 1939-1945” (2007), the British historian Norman Davies begins from the premise that “the war effort of the Western powers” was “something of a sideshow.” America lost 143,000 soldiers in the fight against Germany, Davies points out, while the Soviet Union lost 11 million....