Qutb al-Din Muhammad Ibn Masoud Ibn Musleh Shirazi, known as Qotb al-Din Shirazi, Persian astronomer and physician (1236-1311). He studied logic under “Katebi Qazvini” and philosophy and medicine in the presence of the leading scholar “Khajeh Nasi al-Din Tusi”. In his tow comprehensive astronomical works, he has given what is conceivably the best Arabic account of astronomy (cosmography) with mathematical aids. He also wrote explanations for the books “Canon of medicine” and “The philosophy of illumination”. The book “Pearls of the Crown” (on the kinds of philosophy), is his another work. His fame is for the explanation of “Philosophy of Illumination” (Hekmat al-Ishraq; Suhrawardi’s work).