The monograph by Archpriest Georgy Mitrofanov, a famous historian, Doctor of Theology, Candidate of Philosophy, head of the Department of Church History of the St. Petersburg Theological Academy, was written on the basis of the author’s master’s thesis “The Work of E. N. Trubetskoy as an Experience in the Philosophical Substantiation of a Religious Worldview” (2008 ) and is dedicated to the work in the field of religious philosophy of the outstanding Russian thinker Prince Evgeniy Nikolaevich Trubetskoy (1863-1920). The monograph shows that E. N. Trubetskoy connects the creation by an Orthodox Christian of one or another system of philosophy with an attempt to substantiate his own religious worldview with the principles of this system, which leads to an existential transformation of the personality of the most thoughtful Christian. The monograph is recommended for teachers and students of theological educational institutions, theological faculties of secular universities, as well as everyone interested in Russian religious philosophy. The publishing layout is saved in PDF A4 format.