This article is devoted to the analysis of the distinctive “sociology of Moscow” of the Russian philosopher and sociologist Fyodor Avgustovich Stepun (1884–1965) who was born, studied, and lived in Moscow until his expulsion in 1922 by the Bolshevik regime of Soviet Russia. From a large amount of factual material, the author shows how the creative experiences of the Muscovite Stepun were associated with two different periods of the life of Moscow, “before” and “after” the Revolution of 1917. Before the First World War, Moscow was a favorite theme of steppe-memoirs. Unlike many authors who called those years a “lost time” for Russia, Stepun, on the contrary, highly valued that time period for its social dynamism and diverse cultural creativity. A native Muscovite, Stepun was encouraged by the rapid pre-war growth of the old capital and had repeatedly declared the life in pre-war Moscow to be the “Golden Age” of Russian culture. He shared the idea that an “enlightened Russia” is “a better Europe” with his emigré friends, G. P. Fedotov and V. Wadle. A special place in the article is given to the analysis of Stepun’s attitude as an analyst and memoirist to the radical transformation of the “metaphysical landscape” of Moscow after the revolution; Stepun called it an “existential revolution” that broke all the usual human “identities”. According to Stepun, the Bolshevik Revolution literally produced a tectonic shift of human existence, not only knocking millions of people from their usual contexts of existence, but also stretching the limits of and exposing all of the primary “existential” meanings of human existence.