The text of the Letter of Fr. S. Bulgakov to Hieromonk Afanasy (Petrov) is first published from the original manuscript. It was written at the height of the famous «dispute on Sophia». The Bulgakov’s understanding of the sense of his own way of theology is discussed as well as his attitude to existent events and their main participants. The text is supplied with the substantial introduction which specifies the context and circumstances of its appearance, and gives detailed commentary to personalia and main problems related to it.