This book offers a new critical edition, translation, and commentary of the second maqala – onoptics and theory of vision – of the 8th century AH/AD 14th century Kitab nur al-?uyun wa-gami?al-funun. The Kitab nur al-?uyun wa-gami? al-funun is a significant medieval Arabic treatise onophthalmology. This book focuses on the second “discourse” or maqala, which deals with opticsand theories of vision. Readers will gain a new understanding of the treatment of optics in a latemedieval Arabic medical work; in particular, the extensive part on Euclidean geometrical optics,where the methodology of mathematics is adopted, makes this work unique in the context ofmedieval Arabic ophthalmology. The critical edition is accompanied by an English translation,detailed commentary, and introduction that situates the work in its historical and intellectualcontext. This book will be of interest to students and scholars working on the history of premodern Arabic science, particularly optics and medicine, as well as historians of premodern science more generally, codicologists, paleographers, and those working on Arabic literary history.