an excerpt from the Introduction: THE present work may possibly attract the attention of some scholars and students of comparative religion. It is a semi-official defence of Islam written at the command, with the assistance, and in the court of the Caliph Mutawakkil (A.D. 847-861); the adversaries more frequently attacked are the Christians, who, thanks to their numerical strength, to the vigilance of the East-Syrian Patriarchs residing in Baghdad, and to the influence of a successive series of court-physicians, were the strongest opponents of the State religion at the time of the Abbasid dynasty; in the second rank come Jews, Hindus, Buddhists, and Parsees, who, however, are more severely handled. The work is also likely to throw great light on the religious tendencies of Muhammadanism at the time of its greatest expansion and orthodoxy. It is not our intention to give here a synopsis of the general plan adopted in the execution of the work, nor to express an opinion on its intrinsic merits and demerits. We leave the reader to draw his own conclusions on the subject; but in order to help him in his task we have ventured to add a few short notes to some statements which, to use a sentence of the authors, not two learned men can regard as irrefragable.   1 A short essay in this direction was published in J.R.A.S., 1920,     pp. 481-488. In some respects it is the weightiest of all the works     on Islam that we have read for a long time, and during the last seven     years we have perused more than seven hundred Arabic MSS. on different     subjects. The author has displayed a literary art which has certain     merits of its own, and which, from many sentences such asif the adversaries     shout" appears to have been dictated to him by a series of public discussions     held in the court of Mutawakkil. The second half of the eighth and the first half of the ninth centuries were, owing to the somewhat tolerant attitude of the Caliphs of Baghdad, marked by the first serious shock of opinion between Christians and Muslims. It was at this time that, in answer to certain objections advanced by Christians, the ingenuity of the Muslim writers gathered from scattered materials and purely oral sources the weapons which in the same field of controversy would place them on even terms with their seemingly more favoured opponents. We do not believe that the imposing number of Muhammads miracles and prophecies (with which we should compare Quran, xxix 49; xiii. 27-30; xvii. 92-97) would have been so skilfully elaborated at so late a date as the eighth century, if their compilers had not been forced so to act by ready adversaries who had made the subject of thaumaturgy a special point in their polemics against them. We have here and there isolated cases of public discussions before this period. The earliest and the most important record seems to be the colloquy which took place in Syria between the Arab generals and the Monophysite Patriarch of Antioch, John I., in the eighteenth year of the Hijrah Sunday, 9th May, A.D. 639). The Syriac text of this document has been published by F. Nau,[1] and we have given a summary of it in the Journal of the Manchester Egyptian and Oriental Society (1916, p. 35 seq.). On the other hand, we know nothing about the discussion between the Umayyad Abdul-Malik b. Marwan (A.D. 692-705) and Ibrahim, son of Rahib (monk) Tabarani.