For centuries the Jesus Prayer has been leading Orthodox Christians beyond the language of liturgy and the representations of iconography into the wordless, imageless stillness of the mystery of God. In more recent years it has been helping a growing number of Western Christians to find a deeper relationship with God through the continual rhythmic repetition of a short prayer which, by general agreement, first emerged from the desert spirituality of early monasticism. In this study James Wellington explores the understanding and practice of the psalmody which underpinned this spirituality. By means of an investigation of the importance of psalmody in desert monasticism, an exploration of the influence of Evagrius of Pontus and a thorough examination of selected psalm-commentaries in circulation in the East at this time, he reveals a monastic culture which was particularly conducive to the emergence of a Christ-centred invocatory prayer.