STANLEY LANE-POOLE: Studies in a Mosque. II edition. London, 1893. Miscellaneous essays, lightly written but trustworthy.
KREHL: Beiträge zur Characteristik, der Lehre vom Glauben in Islam. Leipzig, 1877.
G. VON VLOTEN: Les Hachwia et Nabita. Eleventh Congress of Orientalists, part iii, pp. 99 ff. On early religious sects.
G. VON VLOTEN: Irdja. ZDMG, xiv, pp. 181 ff. On the Murji'ites.
EDUARD SACHAU: Über de religiosen Anschauungen der ibaditischen Muhammedaner in Oman and Ostafrica. Mitth. a. d. Sem. f. Orient. Sprachen. Berlin, 1899.
H. STEINER: Die Mu'taziliten oder die Freidenker im Islam. Leipzig, 1865.
WILHELM SPITTA: Zur Geschichte Abu l-Hasan al-Ash'ari's. Leipzig, 1876. The best as yet on al-Ash'ari, but to be used with caution, especially in the translations of theological texts.
MARTIN SCHREINER: Zur Geschichte des Ash-aritenthums. In Actes du huitieme Congress International des Orientalistes, I, i, pp. 77 ff. Leiden, 1891.
M. A. F. MEHREN: Exposé de la reforme de l'Islamisme commencee au troisieme siecle de l'Hegire par Abou-l-Hasan Ali el-Ash'ari et continuee par son ecole. Third International Congress of Orientalists, vol. ii.
G. FLÜGEL: AL-Kindi genannt "der Philosoph der Araber." Ein Vorbild seiner Zeit and seines Volkes. Leipzig, 1857.
SIR WILLIAM MUIR: The Apology of al-Kindy, Written at the court of al-Mamun. London, 1882.
E. SELL: The Faith of Islam. London, 1896. II edittion. A valuable book, but from the point of view of an Indian missionary. Hence the tone is polemic and the technicalities are Persian rather than Arabic. 
WALTER M. PATTEN: Ahmad ibn Hanbal and the Mihna. Leyden, 1897. There is a valuable review by Goldziher in ZDMG, lii, pp. 155 ff. It traces connection of Hanbalites with Ibn Taymiya and Wahhabites.
HEINRICH RITTER: Ueber unsere Kenntniss der Arabischen Philosophie. Gottingen, 1844.
FRIEDRICH DIETERICI: Alfarabi's philosophische Abhandlungen herausgegeben. Leiden, 1890. Aus den arabischen Übersetzt. Leiden, 1892.

AL-FARABI: Der Musterstaat. Herausgegeben and Übersetzt von Frdr. Dieterici. Leiden, 1900.
G. FLÜGEL: Ueber Inhalt and Verfasser der arabischen Encyclopädie der lkhwan as-Safa. ZDMG, xiii, pp. 1 ff. See, too, an excellent article by August Muller in Ersch und Gruber, ii, 42, pp. 272 ff., and Stanley Lane-Poole in his Studies in a Mosque.
FRIEDRICH DIETERICI: Die Philosophie der Araber im X. Jahrhundert n. Chr. aus der Schriften der lauteren Brüder herausgegeben. Berlin and Leipzig, 1861-1879.
IGNAZ GOLDZIHER: Materialien zur Entwickelungs-geschichte des Sufismus. WZ, xiii, pp. 35 ff.
THEODOR NÖLDEKE: Sufi. ZDMG, xlviii, pp. 45 ff. On the derivation and early usage of the name Sufi.
ADELBERT MERX: Idee and Grundlinien einer allgemeinen Geschichte der Mystik. Heidelberg, 1898.
JOHN P. BROWN: The Derwishes or Oriental Spiritualism. London, 1868. A valuable but uncritical description of modern Turkish and Persian Darwishes.
SIR JAMES REDHOUSE: The Mesnevi of Jelal eddin ar-rumi translated into English. Book I. London, 1881. See, too, a translation by Whinfield, London, 1887, and an edition of selected ghazels from the Diwan with translation and valuable introduction by R. A. Nicholson, Cambridge University Press, 1898.
E. J. W. GIBB: A History of Ottoman Poetry. Vol. i. London, 1900. A valuable statement of the later Persian and Turkish mysticism and metaphysic on pp. 13-70.
E. H. PALMER: Oriental Mysticism. Cambridge, 1867.
CARRA DE VAUX: Avicenne. Paris, 1900. Contains an introductory sketch of philosophy and theology up to the time of Ibn Sina. Algazali. Paris, 1902. A continuation of the first.
A. VON KREMER: Uber die philosophischen Gedichte des Abul Ala Ma'arry. Wien, 1888.
A. VON KREMER: Gedichte des Abu-l-Ala Ma'arri. ZDMG, xxix, 304 ; xxx, 40 ; xxxi, pp. 471 ff.; xxxviii, 499 ff.
ABU-L-ALA AL-MA'ARRI: Letters Arabic and English, with notes, etc., edited by D. S. Margoliouth. Oxford, 1898. See, too, papers by R. A. Nicholson in JRAS, October, 1900, ff.; and by Margoliouth, for April, 1902.
E. FITZGERALD: The Ruba'iyat of Omar Khayyam. With a Commentary by H M. Batson and a biographical Introduction by