Sergei O. Prokofieff, Russian anthropologist and author (b. 1954)
Sergei Olegovich Prokofieff (16 January 1954 – 26 July 2014) was a Russian anthroposophist. He was the grandson of the composer Sergei Prokofiev and his first wife Lina Prokofiev, and the son of Oleg Prokofiev and his first wife Sofia Korovina. Born in Moscow, he studied fine arts and painting at the Moscow School of Art. He encountered anthroposophy in his youth, and soon made the decision to devote his life to it.Prokofieff, who published as Sergei O. Prokofieff, wrote his first book, Rudolf Steiner and the Founding of the New Mysteries, while living in Soviet Russia. The book was first published in German in 1982 and in English translation in 1986. After the collapse of the Soviet Union, he was a co-founder of the Anthroposophical Society in Russia. At Easter 2001, he became a member of the Executive Council of the General Anthroposophical Society in Dornach, Switzerland.Prokofieff was a prolific author; at the core of his work is an attempt to develop a deepened understanding of Christianity on the basis of Rudolf Steiner's spiritual-scientific research. In 1989, Prokofieff wrote The Spiritual Origins of Eastern Europe and the Future Mysteries of the Holy Grail, a book which analysed the spiritual currents affecting Russia and the Slavonic world generally and in relation to worldly societal and geopolitical events and change.

Later in his life, Prokofieff wrote two works, The Case of Valentin Tomberg and Valentin Tomberg and Anthroposophy: a problematic relationship, in which he put forward the view that Valentin Tomberg, the Christian Hermeticist, and author (like Prokofieff) of profound Christian occultic books, developed, in his later years, into an apologist for Jesuitism (that term being understood or used, however, in a specifically Anthroposophical sense, not simply relating to the Jesuits as usually understood).

Prokofieff's widow Astrid survived him.