München: G.H. Beck, 1923, complte set in two volumes, xvi,557;x,635 pp. original linen bindings, in good state. Armorial bookplate of J. Havelaar. Written by Oswald 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 organic 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.