Essays on Karl Jaspers, Rosa Luxemburg, Pope John XXIII, Isak Dinesen, Bertolt Brecht, Randall Jarrell, and others whose lives and work illuminated the early part of the century. Index. Hannah Arendt (1906–1975) is considered one of the most important and influential thinkers of the twentieth century. A political theorist and philosopher, she is also the author of Crises of the Republic , On Violence , The Life of the Mind , and Men in Dark Times . The Origins of Totalitarianism was first published in 1951.