The focus of this study is the final part of Dionysius bar Salibi’s polemical work against the Muslims, which contains a number of quotations from the Qur’an in Syriac translation. Mingana makes certain claims about the importance of these Syriac quotations for the history of the Qur’anic text. His introduction examines views about the standardization of the text of the Qur’an (with several references and quotations to Arabic writers) and generally considers Syriac evidence for the subject. Mingana translates this part of bar Salibi’s work and comments on several parts of it. A manuscript facsimile is included, followed by an appendix dealing with a Harvard manuscript of bar Salibi’s work. The entire treatise has subsequently appeared (with English translation), but Mingana’s controversial investigation remains necessary reading for anyone interested in the history of the Qur’anic text and Muslim-Christian relations in the 12th century.