Light is a discursive tool that Sufis have drawn upon over the centuries in order to elucidate systems of thought and practice. In medieval Islamic thought, light was closely associated with the soul as well as conceptions of sight and the eye. It also occupied an important place in cosmology. By the twelfth- and thirteenth-centuries, Sufis began to consider notions of light more systematically, creating close correspondences between vision, cosmology, and anthropology within Sufi thought. This coincided with the increased production (...) of complex diagrams in Sufi texts. This article shows that these developments were interrelated. By analyzing Shams al-Dīn al-Daylamī’s diagrams alongside his theories of light with respect to the nature of the soul and body, it demonstrates that the theory of the soul as light played an important part in shaping Sufi thought, practice, and visual culture. (shrink)