The book of the Orthodox theologian and patrolologist, Doctor of Philosophy of the University of Oxford, Doctor of Theology of the St. Sergius Orthodox Theological Institute in Paris, Bishop Hilarion (Alfeev) is the first monograph in modern theological science dedicated to the great Father of the Church of the 7th century. Based on the material of the widely known “Words” ascetic”, as well as the recently opened Conversations “On the Divine Mysteries and the Spiritual Life” of Isaac the Syrian, the author reconstructs the theological system of the Syrian writer-hermit, analyzes his ascetic and mystical teaching. The book is about God's love for man and man's love for God, about temptations and abandonment by God, about humility and tears of repentance, about prayer and mystical insights, about life after death and about the last times. For everyone who strives to get closer to God.