The Optics of Ibn al-Haytham Books IV–V: On Reflection and Images Seen by Reflection

The *Optics *by Ibn al-Haytham, perhaps the greatest mathematician and physicist of the medieval Arabic/Islamic world, set the scene for the entire development of the science of optics both within the Islamicate realm and subsequently in the Western world. This new English translation of Books IV–V, which is a study of reflection and refraction of light and of vision produced by reflected and refracted rays, is presented with an introduction and critical analysis.

Ibn al-Haytham (c.965–c.1040) is perhaps the greatest mathematician and physicist of the medieval Arabic/Islamic world. His reputation is based not only on the vast amount of material he was able to process, but also on his rigorous scientific methodology. The most famous book in which he applies his scientific method is his *Optics *(in Arabic: Kitāb al-manāẓir) in which he deals with both the mathematics of rays of light and the physical aspects of the eye in seven comprehensive books. His reinstatement of the entire science of optics sets the scene for the whole of the subsequent development of the subject, both within the Islamicate realm and, through a twelfth–thirteenth-century translation, in the Western world, influencing figures such as William of Ockham, Kepler, Descartes, and Christaan Huygens.

The immense work of editing, translating into English, and commenting on this work was undertaken by Abdelhamid I. Sabra. This English translation of Books IV–V – a study of reflection and refraction of light and of vision produced by reflected and refracted rays – was completed by Sabra with an introduction and critical analysis before his death in 2013, and has been prepared for publication by Jan Hogendijk.