This book is a study of the role of mystical discourse and experience can play in Christian-Muslim dialogue as a subset of interfaith dialogue in general. It concentrates on the work of two great medieval mystic masters, one Muslim, the other Christian. The Christian is a German Dominican mystic, Mesiter Eckhart. The Muslim is Muhyi al-Din al-Arabi, a Sufi teacher known as the Greatest Master. It tries to articulate conversation points between the two discourses which might serve as nodes for a possible new matrix for Christian-Muslim dialogue.