JOSEPH BEN AḤMAD IBN ḤASDAI:
Egyptian physician and medical writer; lived in Cairo at the beginning of the twelfth century. Although his biographer, Ibn Abi Uṣaibi'ah, does not affirm his Jewish descent, there is no doubt that Joseph belonged to the Judæo-Spanish family of Ḥasdai. Early in life he went to Egypt, where he found a protector in the vizier Ma'mun Abu 'Abd Allah ibn Nur al-Daulah al-'Amiri. Joseph carried on a scientific correspondence with the Arabic philosopher Avempace (Ibn Baja). He was the author of the following works: "Al-Sharḥ at-Ma'muni," commentary on Hippocrates' work on the oath ("Kitab al-Iman"); "Sharḥ al-Fuṣul" commentary on the first book of Hippocrates' "Aphorisms"; "Ta'aliḳ"; "Fawa'id," extracts from Ali ibn Riḍwan's commentary on Galen's work on nature; "Al-Ḳaul 'ala Awwal al-Ṣina'ah al-Ṣaghirab," on Galen's first book of "Ars Parva"; "Al-Ajmal," on logic, with notes.
- Ibn Abi Uṣaibi'ah, ii. 51; Hammer-Purgstal, Literaturgesch. der Araber, vi. 481, No. 615; vii. 505;
- Steinschneider, Die Arabische Literatur der Juden, § 100.