The Decline of the West (Der Untergang des Abendlandes), Oswald Spengler's monumental philosophical and historical work, is a sweeping analysis of world history through the lens of cultural morphology. Originally published in two volumes (Vol. I in 1918 and Vol. II in 1922), the work challenges linear, Eurocentric views of history and presents a cyclical theory of civilizations rising, flourishing, and eventually declining. Spengler proposes that cultures are like living organisms — each with a distinct soul, life-span, and destiny. He examines eight major high cultures, including the Classical (Greco-Roman), Indian, Chinese, and Western (or "Faustian") civilizations, and outlines how each passes through stages of birth, growth, fulfillment, and inevitable decline. According to Spengler, the West was in the final stage of "Civilization," a period marked by rationalism, urbanization, and the withering of spiritual vitality. Volume I, Form and Actuality, introduces his key ideas and lays out the philosophical foundation of his cyclical model, while Volume II, Perspectives of World History, provides historical detail, comparative analysis, and predictions about the West's future trajectory. Provocative and often controversial, The Decline of the West influenced 20th-century thought across disciplines — from history and philosophy to politics and cultural criticism. Whether embraced or contested, Spengler's vision of history as a non-linear and deeply symbolic process continues to inspire debate and reflection on the fate of modern civilization.