Jacob al-Qirqisānī(Abū Yūsuf Ya‘qūb ibn Isḥāq ibn Sama‘wayh al‑Qirqisānī) was a Karaite polymath whose major extant work, Kitāb al-Anwār wa ʾl-Marāqib (Book of Lights and Watchtowers), was written in 937. Little is known about his life, although his nisba indicates Qarqisiyyah (the ancient town of Circesium) on the eastern bank of the Euphrates near its confluence with the Khābūr River. Some of his writingsmay have been based upon personal experience, including travel in Persia and India. 

His Kitāb al-Anwārwa ʾl-Marāqib is a massive work that includes law, exegesis, philo…