The history of optics was transformed in the eleventh century by the work of Ibn al-Haytham, often known as Alhazen. Before his work, the dominant theories of vision were either 'extramission,' which claimed that the eye emitted rays to touch objects, or 'intromission,' which claimed that objects shed physical skins that entered the eye. Alhazen rejected both, using a combination of mathematical geometry and experimental physics to prove that vision occurs because light rays reflect off objects and enter the eye. His masterpiece, 'Book of Optics,' established the principle that light travels in straight lines and used a camera obscura to demonstrate how images are projected. When his work was translated into Latin in the late twelfth century, it provided the foundation for the European development of lenses, spectacles, and eventually the telescope. However, Alhazen's impact was not limited to the study of light. By insisting that any physical theory must be tested through repeatable experiments, he is often cited as the father of the modern scientific method. His work represents a crucial interdisciplinary bridge, combining the ancient Greek tradition of geometry with a new, experimental approach to the physical world. It shows that the foundations of modern Western science are deeply rooted in the intellectual achievements of the Islamic Golden Age.