David Thomas, PhD (1983) in Islamic Studies, University of Lancaster, is Professor of Christianity and Islam at the University of Birmingham. He has published widely on Christian-Muslim relations, and among his most recent works is Christian Doctrines in Islamic Theology (Brill, 2008).Barbara Roggema has a Ph.D. in Languages and Cultures of the Middle East (University of Groningen, 2007) and is lecturer in the History of the Islamic World at John Cabot University (Rome). Her most recent publication is The Legend of Sergius Baḥīrā. Eastern Christian Apologetics and Apocalyptic in Response to Islam (Brill, 2008).