Rifaat Y. Ebied is Emeritus Professor of Semitic Studies at the University of Sydney. He has published extensively in the field of Semitic Studies generally and on Christian Arabic and Syriac Studies as well as Christian-Muslim relations in particular, most recently The Polemical Works of ‘Alī al-Ṭabarī (with David Thomas) (Brill, 2016).Malki Malki is the Syrian Orthodox Archbishop of Australia and New Zealand. He has published translations and a number of articles on the Bible, Liturgy and Syriac language, most recently Patriarch Ignatius Bar Wahīb’s (d. 1333) Treatise on the Six Letters that have Two Sounds (with Rifaat Ebied) (2017). Lionel R. Wickham † was curate at Boston, Lincs, UK; formerly Lecturer in the Faculty of Divinity, University of Cambridge. His publications included many articles and editions in the field of Patristics, most recently his highly regarded Select Letters of Cyril of Alexandria (OUP, 1983).