Oswald Arnold Gottfried Spengler was a German polymath, whose areas of interest included history, philosophy, mathematics, science, and art, as well as their relation to his organic theory of history. He is best known for his two-volume work The Decline of the West, published in 1918 and 1922, covering human history. Spengler's model of history postulates that human cultures and civilizations are akin to biological entities, each with a limited, predictable, and deterministic lifespan.

History is the systematic study and documentation of the human past.