Gustav Weil fit ses études à l’Ecole Talmudique de Metz et étudia l’histoire et l’arabe à Paris et Heidelberg. Il travailla pendant plusieurs années en Égypte en tant que traducteur, et où il perfectionna son arabe, et appris le persan et le turc. Il a finalement terminé sa carrière en tant que professeur à l’Université de Heidelberg.
(Source : Jewish encyclopedia)
Extrait de sa biographie 
At Stuttgart in 1837 Weil published "Die Poetische Literatur der Araber," and later issued a translation of the "Thousand and One Nights," the first complete translation from the original text into German (4 vols., 1837-41; 2d ed. 1866; 4th ed. 1871-72), which was, however, spoiled in the process of publication. Weil purposed to give a philologically exact version, which would have been highly desirable in many respects; but the Stuttgart publisher authorized August Lewald to change many objectionable passages, and thus made of it a popular and salable work. This perversion caused Weil much vexation. Weil’s second great work was "Mohammed, der Prophet" (Stuttgart, 1843), a life of Mohammed, in the compilation of which he was the first to go back to the oldest accessible sources in Europe. It was not in his nature, however, to attempt a psychological reconstruction of the prophet’s character, as was done later by Sprenger and Muir. Washington Irving in his "Life of Mohammed" used Weil’s work as a source of information, and acknowledged his indebtedness to that author.
While pursuing these studies Weil published his "Historisch-Kritische Einleitung in den Koran" (Bielefeld and Leipsic, 1844 and 1878) as a supplement to Ullman’s translation of the Koran, and the translation of one of the original sources of the biography of Mohammed, "Leben Mohammed’s nach Muhammed ibn Isḥaḳ, Bearbeitet von Abd el-Malik ibn Hischâm" (Stuttgart, 2 vols., 1864). Three additional essays remain to be mentioned: one on Mohammed’s epilepsy ("Journal Asiatique," July, 1842); the second an investigation of a "Supposed Lie of Mohammed" (ib. May, 1849); and the third a discussion of the question whether Mohammed could read and write ("Proceedings of the Congress of Orientalists at Florence," i. 357). To these must be added "Biblische Legenden der Mohammedaner" (Frankfort, 1845), in which Weil proves the influence of the rabbinic legends upon the religion of Islam.
The most comprehensive work of Weil is his "Geschichte der Chalifen" (5 vols., Heidelberg and Stuttgart, 1846-51), which is virtually an elaboration of the original works of Mohammedan historians, whom he in large part studied from manuscripts; it treats also of the Egyptian and Spanish califates. This was followed by the "Geschichte der Islamischen Völker von Mohammed bis zur Zeit des Sultans Selim." (Stuttgart, 1866), an introduction to the medieval history of the Orient. After 1866 Weil confined his literary activity to the publication of reviews in the "Heidelberger Jahrbücher" and in the "Jenaische Litteratur-Zeitung." In later years he received honors from various states, including Baden and Prussia. Owing to continued illness he was pensioned in 1888.
Weil’s collection of Arabic manuscripts was presented to the University of Heidelberg by his children.
Bibliography: Von Weech, Badische Biographien, iv. 489-496, Carlsruhe, 1891;
Allgemeine Deutsche Biographie, xli. 486-488, Leipsic, 1896;
Meyers Konversations-Lexikon.S. E. O. A. M.
(Source : Jewish encyclopedia)
– Historisch-kritische Einleitung in den Koran, Velhagen und Klasing, 1844.
– Geschichte der islamitischen Völker von Mohammed bis zur Zeit des Sultans Selim übersichtlich dargestellt, Rieger, 1866
– Das Leben Mohammed’s nach Mohammed ibn Ishak, Ibn Isḥāq, Muḥammad (704?-767?), J. A. Metzler, 1864
– Geschichte der Chalifen, [s.n.], 1846-1862
– Biblische Legenden der Muselmänner, J. Rütten, 1845; traduction en anglais sous le titre "The Bible, the Koran, and the Talmud, or, Biblical legends of the Mussulmans", Harper, 1846.
– Mohammed der Prophet, sein Leben und seine Lehre, J. B. Metzler, 1843.