The French political philosopher Raymond Aron once observed that the 20th century could have been Germany's century. In 1900, the country was continental Europe's leading power, its material strength and strident militaristic ethos apparently balanced by a vital culture and extraordinary scientific achievement. It was poised to achieve greatness. In this work, the eminent historian Fritz Stern explores the ambiguous promise of Germany before Hitler, as well as its horrifying decline into moral nihilism under Nazi rule, and aspects of its remarkable recovery since World War II. He does so by gracefully blending history and biography in a sequence of finely drawn studies of Germany's great scientists and of German-Jewish relations before and during Hitler's regime. Stern's central chapter traces the complex friendship of Albert Einstein and the Nobel Prize-winning chemist Fritz Haber, contrasting their responses to German life and to their Jewish heritage. Haber, a convert to Christianity and a firm German patriot until the rise of the Nazis; Einstein, a committed internationalist and pacifist, and a proud though secular Jew. Other chapters, also based on new archival sources, consider the turbulent and interrelated careers of the Physicist Max Planck, an austere and powerful figure who helped to make Berlin a happy, productive place for Einstein and other legendary scientists; of Paul Ehrlich, the founder of chemotherapy; of Walther Rathenau, the German-Jew industrialist and statesman tragically assassinated in 1922; and of Chaim Weizmann, chemist, Zionist and first president of Israel, whose close relations with his German colleagues are here for the first time recounted. Stern examines the still-controversial way in which historians have dealt with World War I and Germans have dealt with their nation's defeat, and he analyses the conflicts over the interpretations of Germany's past that persist to this day.