Physicist Jim al-Khalili reveals how Islamic thinkers played a crucial role in explaining light and optics. Playing a vital role in our everyday lives, technologies based on light are in use all around us. From art and science to modern technology, the study of light - and how it behaves and interacts with matter has intrigued scientists for over a century. 2015 marked the 1,000th anniversary of the Kitab al-Manazir (The Book of Optics), a seven-volume treatise written by the Iraqi scientist Ibn al-Haytham - a pioneering thinker whose views have been crucial to our understanding of how the universe came into existence.