Fr. Sergei Nikolaevich Bulgakov (Russian: Серге́й Никола́евич Булга́ков) (28 June [O.S. 16 June] 1871 - July 12, 1944) was a Russian Orthodox Christian theologian, philosopher and economist. Until 1922 he worked in Russia; afterwards in Paris.

Sergei Nicolaevich Bulgakov was born on 16 June 1871 Old Style to the family of an Orthodox priest (Nikolai Bulgakov) in the town of Livny, Oryol guberniya, in Russia.

He studied at Orel seminary, then at Yelets gimnasium. In 1894 he graduated from the Law School of Moscow University, where he had also undertaken a serious study of political economy.

During his study at the seminary Bulgakov became interested in Marxism and took part in the Legal Marxism movement. Studying Marxism, Bulgakov eventually became convinced of the impotence of this theory. Under the influence of works of Russian religious thinkers (Leo Tolstoy, Fyodor Dostoyevsky, Vladimir Solovyov, etc.), in the course of his meetings and arguments with Leo Tolstoy he found his religious beliefs again. He wrote a book about his evolution (Sergey Bulgakov, From Marxism to Idealism, 1903). Such an evolution was common for the Russian intelligentsia of the time, and he soon became one of their recognised ideologists. A primary contributor to the books Problems of Idealism (1902), Vekhi, Problems of Religion, About Vladimir Solovyev, About the Religion of Leo Tolstoy, The Religion of Solovyov's Philosophical Society, he participated in the journals New Way (Новый Путь) and Questions of Life (Вопросы Жизни). He was a leader of the publisher Way (Путь, 1911–1917), where he printed many important works of contemporary Orthodox theology.

Mikhaíl Afanasyevich Bulgakov (Russian: Михаи́л Афана́сьевич Булга́ков, pronounced [mʲɪxɐˈil ɐfɐˈnasʲjɪvʲɪtɕ bʊlˈgakəf]; May 15 [O.S. May 3] 1891, Kiev – March 10, 1940, Moscow) was a Soviet Russian writer and playwright active in the first half of the 20th century. He is best known for his novel The Master and Margarita, which The Times of London has called one of the masterpieces of the 20th century.

Mikhail Bulgakov was born on May 15, 1891 in Kiev, at that time in the Russian Empire. He was one of seven children (the oldest of three brothers) of Afanasiy Bulgakov, an assistant professor at the Kiev Theological Academy, and Varvara Mikhailovna, a former teacher. Both of his grandfathers were clergymen in the Russian Orthodox Church. Friendship, respect, and mutual love reigned in Bulgakov's large family and happy home. From childhood Bulgakov was drawn to theater. At home, he wrote comedies, which his brothers and sisters acted out.

In 1901 Bulgakov joined the First Kiev Gymnasium, where he developed an interest in Russian and European literature (his favourite authors at the time being Gogol, Pushkin, Dostoyevsky, Saltykov-Shchedrin, and Dickens), theatre and opera. The teachers of the Gymnasium exerted a great influence on the formation of his literary taste. After the death of his father in 1907, Mikhail's mother, a well-educated and extraordinary diligent person, assumed responsibility for his education. After graduation from the Gymnasium in 1909, Bulgakov entered the Medical Faculty of St. Vladimir University, which he finished with special commendation to become a physician at the Kiev Military Hospital.