In the fourth volume of the British prime minister's legendary wartime speeches, the tides are turning and an Allied victory is within reach.   The brilliant politician and military strategist Winston S. Churchill was a master not only of the battlefield, but of the page and the podium. Over the course of forty books and countless speeches, broadcasts, news items and more, he addressed a country at war and at peace, thrilling with victory but uneasy with its shifting role in global politics. In 1953, he was awarded the Nobel Prize for Literature for "his mastery of historical and biographical description as well as for brilliant oratory in defending exalted human values." During his lifetime, he enthralled readers and brought crowds roaring to their feet; in the years since his death, his skilled writing has inspired generations of eager history buffs.   As WWII enters its final years and the US enters the fighting, an Allied victory is tantalizingly within reach. This period saw President Roosevelt's proposal of the "unconditional surrender" policy; the defeat of Mussolini and Rommel; Russia's dominance over Axis forces at Stalingrad; and a powerful new bombing campaign bringing the air conflict to the heart of Germany.   Suddenly, victory seemed within the Allies' grasp. In this fourth volume of Churchill's famous wartime speeches, his stirring tone takes on an edge of hope and a glimmer of the triumph to come, as Britain rallied from the Blitz and readied itself for the final push.