Harald Motzki, Ph.D. (1978) in Islamic Studies, University of Bonn, is Professor emeritus of Islamic Studies at Radboud University Nijmegen. He has published extensively on Muslim traditions and Islamic social and legal history.Nicolet Boekhoff-van der Voort, Ph.D. (2012) in Religious Studies, Radboud University Nijmegen, is Lecturer of Arabic and Islam at Radboud University Nijmegen. She is currently preparing a book on the biography of the Prophet Muḥammad as transmitted by Ibn Shihāb al-Zuhrī.Sean W. Anthony, Ph.D. (2009) in Near Eastern Languages and Civilizations, University of Chicago, is Assistant Professor of Islamic History at the University of Oregon. He is also the author of The Caliph & the Heretic: Ibn Sabaʾ and the Origins of Shiʿism (Brill, 2012).