Boris Nikolaevich Bugaev (Russian: Бори́с Никола́евич Буга́ев; IPA: [bɐˈrʲis nʲɪkɐˈlajɪvʲɪtɕ bʊˈɡajɪf]), better known by the pen name Andrei Bely (Russian: Андре́й Бе́лый; IPA: [ɐnˈdrʲej ˈbʲelɨj]; 26 October [O.S. 14 October] 1880 – 8 January 1934), was a Russian novelist, poet, theorist, and literary critic. His novel Petersburg was regarded by Vladimir Nabokov as one of the four greatest novels of the 20th century.
Boris Bugaev was born in Moscow, into a prominent intellectual family. His father, Nikolai Bugaev, was a leading mathematician who is regarded as a founder of the Moscow school of mathematics. His mother was not only highly intelligent but a famous society beauty, and the focus of considerable gossip. Young Boris was a polymath whose interests included mathematics, biology, chemistry, music, philosophy, and literature. He would go on to take part in both the Symbolist movement and the Russian school of neo-Kantianism. Bugaev became friendly with Alexander Blok and his wife; he fell in love with her, which caused tensions between the two poets.
Nikolai Bugaev was well known for his influential philosophical essays, in which he decried geometry and probability and trumpeted the virtues of hard analysis. Despite—or because of—his father's mathematical tastes, Boris Bugaev was fascinated by probability and particularly by entropy, a notion to which he frequently refers in works such as Kotik Letaev.