The turn of the twentieth century was an exciting time marked by the discovery of new, previously unsuspected worlds below the surface of everyday perception. Germany, Austria and Switzerland were at the forefront of literary, scientific and artistic innovation at that time. In psychology, Sigmund Freud’s work found explanations hidden in the depths of the unconscious. In the sciences, Röntgen’s 1895 discovery of the X-ray and Rutherford’s 1911 splitting of the atom revealed previously invisible physical realities. In politics, Marx and Engels proposed that labor and capital were the forces determining social change and the progress of history. This time of great optimism and scientific advance also witnessed the outbreak of the First World War, a violent and technological war that questioned the optimism about the continuing progress of humankind. Artists and writers responded to these new ideas in highly imaginative ways. Expressionist artists such as Franz Marc and Wasilly Kandinsky of the “Blaue Reiter” group believed their art revealed a “spiritual” dimension that could balance a society dominated by rationalism. Writers such Kafka, Brecht, Schnitzler and Kästner took their readers into these new worlds in their prose and poetry.