After five introductory chapters, the author proceeds to arrange his book into two great divisions; the one comprising the Religious, the other the Philosophical Sects. The former of these contains an account of the various Sects of the followers of Muḥammad, and likewise of those to whom a true revelation had been made (the _Ahlu ’l-Kitáb_, or 'People of the Scripture'), that is, Jews and Christians; and of those who had a doubtful or pretended revelation (_man lahú shubhatu ’l-Kitáb_), such as the Magi and the Manichæans. The second division comprises an account of the philosophical opinions of the Sabæans (Ṣábians), which are mainly set forth in a very interesting dialogue between a Sabæan and an orthodox Muḥammadan; of the tenets of various Greek Philosophers and some of the Fathers of the Christian Church; and also of the Muḥammadan doctors, more particularly of the system of Ibn Síná or Avicenna, which the author explains at considerable length. The work terminates with an account of the tenets of the Arabs before the commencement of Islamism, and of the religion of the people of India. [Sidenote: Grammar and philology.] [Sidenote: The invention of Arabic grammar.] [Sidenote: The philogists of Baṣra.] The science of grammar took its rise in the cities of Baṣra and Kúfa, which were founded not long after Muḥammad's death, and which remained the chief centres of Arabian life and thought outside the peninsula until they were eclipsed by the great ‘Abbásid capital. In both towns the population consisted of Bedouin Arabs, belonging to different tribes and speaking many different dialects, while there were also thousands of artisans and clients who spoke Persian as their mother-tongue, so that the classical idiom was peculiarly exposed to corrupting influences. If the pride and delight of the Arabs in their noble language led them to regard the maintenance of its purity as a national duty, they were equally bound by their religious convictions to take decisive measures for ensuring the correct pronunciation and interpretation of that "miracle of Divine eloquence," the Arabic Koran. To this latter motive the invention of grammar is traditionally ascribed. The inventor is related to have been Abu ’l-Aswad al-Du’ilí, who died at Baṣra during the Umayyad period. "Abu ’l-Aswad, having been asked where he had acquired the science of grammar, answered that he had learned the rudiments of it from ‘Alí b. Abí Ṭálib. It is said that he never made known any of the principles which he had received from ‘Alí till Ziyád[641] sent to him the order to compose something which might serve as a guide to the public and enable them to understand the Book of God. He at first asked to be excused, but on hearing a man recite the following passage out of the Koran, _anna ’lláha baríun mina ’l-mushrikína wa-rasúluhu_,[642] which last word the reader pronounced _rasúlihi_, he exclaimed, 'I never thought that things would have come