Alfred Kerr is remembered as the most influential theater critic in Germany in the 20th century. He praised Henrik Ibsen as the progenitor of modernity, fought for Gerhart Hauptmann, Arthur Schnitzler, Frank Wedekind, and George Bernard Shaw, discovered Robert Musil, opposed the fame of Hermann Sudermann, clashed with Bertolt Brecht, mocked Karl Kraus, and countered Thomas Mann's endless sentences with his concise, pointed statements that clarified the German language. Around 1910, he was revered by young poets, fought against reactionism and the Nazis during the Republic. Goebbels hated him so much that Kerr had to flee into exile in 1933. The years in Paris and London were a descent into hardship and misery. Deborah Vietor Engländer reveals for the first time in this biography the entirety of Alfred Kerr's life and work, much of which is unknown, utilizing previously undiscovered sources.