Ibn Jazla was born a Christian in Karkh, a district of Baghdad, probably circa 1030. He converted to Islam and embraced the Mu'tazilite school, characterized by a strong dominance of logic and rationalism in its approach of Islam. He studied medicine with Sa'id bin Hibatullah (d.1101-2 AD), himself a Christian converted to Islam, and physician to the Caliph Al-Muqtadi (r. 1075-94). Ibn Jazla was later to have the same position to the Caliph. His most famous work, called Taqwim al-Abdan fi Tadbir al-Insan, is a medical synopsis describing the treatment of more than 350 diseases which was translated into Latin in 1280. He also wrote a treatise on Pharmacy, Al-Minhaj fi al-Adwiya al-Murakkaba, for which he was renowned in Baghdad. This work also translated into Latin in which language he is known as Bingezla (R. Shane Tubbs, Ibn Jazlah and his 11th century accounts (Taqwim al-abdan fi tadbir al-insan) of disease of the brain and spinal cord, in J. Neurosurg.: Spine volume 9 September 2008). He was influenced by the works of classical Greek and Byzantine authors but also read Hunayn bin Ishaq (d. 873 AD) and Al-Razi (d. 902 or 935 AD). Ibn Jazla embodies the medical tradition of the 12th and 13th century: of Christian origin, he studied the Antique works and those of his contemporaries, embraced Islam late during his life time (circa 1074 AD), composed major works and eventually ahieved to the most prestigious position in Baghdad. He made important contributions to medicine, notably on the nervous system.
Ibn Jazla dedicated the Minhaj al-Bayan to the Caliph al-Muqtadi. It is an alphabetical list of simple and compound medicines which title can be translated as 'The Pathway of Explanation as to That Which Man Uses'. It was translated into Latin under the title methodica dispositio eorum, quibus homo uti solet. It explains in detail the recipes of each medicine with a profusion of ingredients, each aiming to cure a specific ailment or to improve a state of being. In his earlier works Ibn Jazla for instance stressed the importance of music in the treatment and prevention of diseases.
Interestingly, the Minhaj al-Bayan attracted attention for its culinary contributions (R. Shane Tubbs, op.cit., citing Garbutt N, Hoadley MC, Ibn Jazlah: the forgotten Abbasid gastronome, J Econ Soc Hist Orient 39:42-44, 1996). For the anecdote, Ibn Jazla describes a recipe of a sort of fried crêpe or cake which is seen as an early form of lasagne as the word would be derived from the Arabic lawzinaj. He describes the lawzinaj as finer that qata'if and more quickly digested, but less nutritious (http://www.cliffordawright.com/caw/food/entries/display.php/id/50 from Maxime Rodinson, On the Etymology of Losange, in Petits Propos Culinaire, vol. 23, July 1986, p. 16).
Six copies of the Minhaj al-Bayan are in the British Library, one of which only is earlier and dated AH 489/1096 AD (OR7499). Another copy, dated AH 972/1564 AD is in the Wellcome Historical Medical Library (WMS. Or. 44). Another copy (entirely digitized) is in the Thomas Fischer Rare Books Collection, University of Toronto (https://archive.org/details/minhajalbayanfim00unse). Another copy sold at Christie's, 5 October 2010, lot 85.