The Civil War and the World War II stand as the two great cataclysms of American history. They were our two costliest wars, with well over a million casualties suffered in each. And they were transforming moments in our history as well, times when the life of the nation and the great experiment in democracy--government of the people, by the people, for the people--seemed to hang in the balance. Now, in War Comes Again, eleven eminent historians--including...