Oswald Spengler was a German historian and thinker famous for The Decline of the West, a book that set forth the cyclical theory of the rise and fall of civilizations. He used to be a German patriot and leading competitor of the Weimar Republic, the interwar liberal democracy that preceded the Nazis’ third Reich. But Spengler believed the Nazis too narrow-minded for the sort of cultural rebirth that he felt necessary, and shortly the disillusionment was returned as the Nazis banned his books.