Oswald Manuel Arnold Gottfried Spengler (; 29 May 1880 – 8 May 1936) was a German historian and philosopher of history whose interests included mathematics, science, and art and their relation to his cyclical theory of history. He is best known for his two-volume work, "The Decline of the West" ("Der Untergang des Abendlandes"), published in 1918 and 1922, covering all of world history. Spengler's model of history postulates that any culture is a superorganism with a limited and predictable lifespan.