The article presents a summary review of K. M. Antonov's monograph Religion et Ratio: Religious Life and Ways of Its Reflexive Comprehension (St. Petersburg State University, 2025), which offers the author’s personal “view on the relationship and mutual mediation of religion and the main forms of reflexive practices aimed at it, such as theology, philosophy of religion and religious studies”. The monograph is a significant work for the modern reader, large-scale study of over 500 pages that is encyclopedic in scope, covering a wide range of issues related to the fundamental problems of understanding the nature of such global and cross-historical universal human phenomena as Religio and Ratio (religiosity and rationality). The work is written in a clear and accessible style and suggests rethinking the norms of “objectivity” of religious studies and other related disciplines from the perspective of a representative of an influential modern Russian religious denomination. This study provides ample opportunities to compare the basic concepts of church and secular relations towards understanding the world and a person's place in it, offering important and promising approaches to its description both in terms of content and methodology. The text discusses many topics, including “ethos of faith, religion and experience”, “forms and values of rationality”, “mysticism”, “system of reflexive structures of religious tradition”, “philosophy of religion”, its “objectivity”, “history”, the relationship with “theology”, “religious studies” and “other philosophical disciplines”, especially the “philosophy of religion in Russia”. The purpose of the publication, according to the author, is “to find the language in which the Church can speak to modern people, especially to the young generation; the language which will give the Church an opportunity to feel their pain and find the convincing answer to their questions”.