Old and new, always topical for every believer, the theme of Jesus’ prayer is constantly nuanced by the Niptic Fathers. The present book, drawing on the writings of the Fathers of earlier times, attempts to speak to us today in a language we can understand and to mediate to us the spiritual experience of the Fathers of all ages. The inner work is traced both in its practical and theological aspects, starting from St. Nikodemus, who is a landmark for ecclesiastical and Augustinian literature, as well as from the texts of the Athonite holy abbots of the last two centuries, such as Saints Joseph the Hesychast and his disciples, Siluan the Athonite and Sophronius of Essex, Paisios of the Holy Mountain, Porphyrios the Kavsokalivite, Emilianos of Simonos Petras and others.