We note with sadness the loss of Professor David O. Morgan (1945-2019), who passed away on 23 October after complications while undergoing heart surgery at Harefield Hospital, England. Dr. Morgan graduated from the University of Oxford in 1966 and received his doctorate from the University of London in 1977. He was a Lecturer at the School of Oriental and African Studies (1978-89), Reader in the History of the Middle East at the University of London (1989-99), and then Professor of History and Religious Studies at the University of Wisconsin (1999-2010). Dr. Morgan was a prolific author, with dozens of books and articles as well as over a hundred reviews, but he was especially well known for two monographs that became standard texts in their field: Medieval Persia 1040-1797 (London, 1988 and many reprints) and The Mongols (Oxford, 1986, with numerous reprints and translations). Professor Morgan was a popular teacher and contributed much of his time to professional activities, including the Governing Council of the British Institute of Persian Studies, the editorial board of the Bulletin of the School of Oriental and African Studies, and as editor of the Journal of the Royal Asiatic Society (1987-99). His contributions were celebrated by the Royal Asiatic Society at a ceremony in May 2016, when he was presented with a special issue of the Journal, The Mongols and Post-Mongol Asia: Studies in Honour of David O. Morgan. Professor Morgan authored ten entries for the Encyclopaedia Iranica, including a major article on Čengiz Khan. Professor Morgan will be remembered by those of us who knew him as an affable colleague with a sharp intellect and a ready wit; he will be greatly missed. The staff of the Yarshater Center extend their deepest condolences to his family and many friends.