This book is an inquiry into the mystical thought of Gregory Barhebraeus (1226-1286CE) and its contemporary relevance, to offer a reading of Barhebraeus' mystical texts by bringing them into conversation with critical religious studies and the hermeneutical tradition of philosophy. The methodological focus of my thesis has led me to pay particular attention to the language used for the study of mysticism, and I lay emphasis on finding a new language that avoids the phenomenological assumptions concerning 'mysticism' to attend to the particularity of 'mystic' traditions, such as that of the Syriac mystic tradition inherited by Barhebraeus.