TzviLangermannFELLOWBar-Ilan UniversityTzvi is a professor in the Department of Arabic at Bar-Ilan University. His research interests are: the histories of science, philosophy and religion.2017-2018 1994-1995 Sa'adia Gaon: Continuity and Change among the Jews of Islamic Lands The Day Unit in Antiquity and the Middle Ages Bar-Ilan University