The dangerous summer of 1940 is discussed in innumerable books, but John Lukacs says he found a few especially useful. Chief among them is the second volume of Churchill’s war memoirs, Their Finest Hour —“it’s amazing how well it holds up.” Also crucial to understanding the twentieth century’s most important friendship is the recent three-volume edition of the Churchill-Roosevelt correspondence published by the Princeton University Press. For a British statesman’s assessment of Churchill and Roosevelt once their collaboration came into the open, see Roy Jenkins’s “Winston Churchill and the ‘Natural Captain of the West’ ” in the October/November 1982 issue of American Heritage. France’s brief and inglorious showing against Hitler’s legions—so puzzling in the light of her doggedness during the First World War—is superbly chronicled and traced to its causes by Alistair Home in his book To Lose a Battle: France 1940 . And anyone who wants a sense of the turbulence and disorder of those terrible, sunny weeks—and an absolutely hair-raising adventure story into the bargain—should scare up a copy of Pied Piper , Nevil Shute’s 1942 novel about an elderly Briton trying to shepherd refugee children out of France as the front dissolves around him. And finally, perhaps nothing gives so clear a feeling of America during the summer of 1940 as issues of Life from those months, with their pictures of gutted villages and fleeing peasants scattered between colorful advertisements for Studebakers and JeLL-O.