At Easter 2001, he became a member of the Executive Council of the General Anthroposophical Society in Dornach, Switzerland.
[2] 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.
[3] 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).
Works are listed chronologically according to the original year of publication in German, prior to English translation.