The following is the first attempt which has been made, since the appearance of Munk's excellent sketch , to present in connected form a History of Philosophy in Islam. This work of mine may therefore be regarded as a fresh initiation,--not a completion of such a task. I could not know of all that had been done by others, in the way of preliminary study in this field; and when I did know of the existence of such material, it was not always accessible to me. As for manuscript assistance, it was only in exceptional cases that this was at my disposal.
Conforming to the conditions which I had to meet, I have in the following account refrained from stating my authorities. But anything which I may have taken over, nearly word for word or without testing it, I have marked in foot-references. For the rest, I deeply regret that I cannot duly indicate at present how much I owe, as regards appreciation of the sources, to men like Dieterici, de Goeje, Goldziher, Houtsma, Aug. Müller, Munk, Nöldeke, Renan, Snouck Hurgronje, van Vloten, and many, many others.
Since the completion of this volume an interesting monograph on Ibn Sina  has appeared, which farther extends its survey over the earlier history of Philosophy in Islam. It gives rise to no occasion, however, to alter substantially my conception of the subject. For all bibliographical details I refer the reader to "die Orientalische Bibliographie", Brockelmann's "Geschichte der Arabischen Litteratur", and Ueberweg--Heinze's "Grundriss der Geschichte der Philosophie" II8, p. 213 sqq. In the transcription of Arabic names I have been more heedful of tradition and German pronunciation, than of consistency. Be it noted only that z is to be pronounced as a soft s, and th like the corresponding English sound . In the Index of Personal Names, accents signify length.