West and East by Harry Turtledove

In 1938, two men held history in their hands. One was Adolf Hitler. The other was British prime minister Neville Chamberlain, who, determined to avoid war at any cost, came to be known as "the great appeaser." But Harry Turtledove, the unrivaled master of alternate history, has launched a gripping saga that springboards from a different fateful act: What if Chamberlain had stood up to Hitler? What would the Nazis' next move have been? And how would the war---which Hitler had always regretted waiting eleven months to start---have unfolded and changed our world? Here, Turtledove takes us across a panorama of conflict fueled by ideology and demagoguery. Nations are pitted against nations, alliances are forged between old enemies, ordinary men and women are hurled into extraordinary life-and-death situations. In Japanese-controlled Singapore, an American marine falls in love with a Russian dance hall hostess, while around him are heard the first explosions of Chinese guerilla resistance. On the frontlines of war-ravaged rural France, a weary soldier perfects the art of using an enormous anti-tank gun as a sniper's tool---while from Germany a killer is sent to hunt him down. And in the icy North Atlantic, a U-boat bearing an experimental device wreaks havoc on British shipping, setting the stage for a Nazi ground invasion of Denmark.