Emil Lederer, born in 1882 in Pilsen, ranks among the most influential economists and social scientists of his time. Christian Schneebeck provides the first comprehensive biography of Lederer. He traces Lederer's thought and intellectual development, as well as the formative influences on him, and repeatedly brings the person himself to the fore between work and theory. The author presents Lederer as an innovative, multifaceted, and still contemporary thinker whose scholarly ethos demands publicly advocating the insights he has gained. Lederer's intellectual formation took place around the turn of the century in Vienna, shaped by Marxism and marginal utility theory. Early on, he engaged at the intersection of scholarship and politics. As editorial secretary and later managing editor, he decisively shaped the Archiv für Sozialwissenschaft und Sozialpolitik . At the same time, he was active in Heidelberg, where he built influential circles of scholars and students. He repeatedly assumed political and academic responsibilities-serving on wartime economic commissions, socialization committees, and as a visiting professor in Tokyo. He examined the First World War intensively, not only in a now-famous essay on the sociology of war. Lederer also devoted himself early to the new business cycle theory, which made him a widely cited reference thinker in economics during the 1920s. And when Lederer, a converted Jew and outspoken socialist, fled to the United States in 1933 to escape the National Socialists, he examined from exile the characteristics and mechanisms of modern totalitarianism. Lederer died in 1939 in American exile.