Abū Naṣr ʿAbd Allāh ibn ʿAlī al-Sarrāj (in Arabic: أبو نصرعبدالله ابن علي السرَّاج, in Persian: ابونصر عبدالله بن علی بن محمد بن یحیی سرّاج) (died 988) was a Sunni sheikh and ascetic born in Tūs, Iran. 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.[1]