Abū Naṣr ʿAbd Allāh ibn ʿAlī al-Sarrāj (d. 988) was a Sunni sheikh and ascetic. He traveled widely in the Islamic world, having lived in cities as diverse as Cairo, Tabriz, Ramla, Baghdad, Damascus, Basra, and Nishapur. He is best known for his seminal Kitāb al-luma (Book of Light), which is considered an encyclopedia of the history of early Sufism.