The sixth volume in the official biography: "A milestone, a monument, a magisterial achievement" (Andrew Roberts, author of The Storm of War).   Starting with the outbreak of war in September 1939 and ending with the Japanese attack on Pearl Harbor in December 1941, this volume in the epic biography of Winston S. Churchill draws on remarkably diverse material: from the War Cabinet and other government records to Churchill's own archive and diaries and letters of his private secretariat to the recollections of those who worked most closely with him.   On the day Hitler invaded Poland, Churchill, aged sixty-four, had been out of office for ten years. Two days later, he became First Lord of the Admiralty, in charge of British naval policy and at the center of war direction. In May 1940 he became prime minister, leading his nation during a time of grave danger and setbacks. His first year and a half as prime minister included the Dunkirk evacuation, the fall of France, the Battle of Britain, the Blitz, the Battle of the Atlantic, the struggle in the Western Desert, and Hitler's invasion of Russia.   By the end of 1940, Britain under Churchill's leadership had survived the onslaught and was making plans to continue the war against an enemy of unlimited ambition and ferocious will. One of Churchill's inner circle said: "We who worked with Churchill every day of the war still saw at most a quarter of his daily tasks and worries." Martin Gilbert has pieced together the whole, setting in context much hitherto scattered and secret evidence, in order to give an intimate and fascinating account of the architect of Britain's "finest hour."   "The most scholarly study of Churchill in war and peace ever written." —Herbert Mitgang, The New York Times