Greek and Arab scholars, and later Europeans such as Descartes and Newton all tried to understand light to gain a better understanding of God. Episode one shows how much of modern science's origins came from the desire to penetrate the divine nature of light.

The second programme explores the link between the development of practical tools that manipulate light and the emergence of new ideas. For example, Galileo's observation that the sun did not go around the earth, was made with a telescope that had been invented for Venetian soldiers and traders.

Episode three charts the discovery of the true nature of light and its impact on the modern world. All of today's technologies - electricity, mobile communications and our ability to illuminate the world 24 hours a day - stem from unravelling the mystery of light.

In the final programme Simon Schaffer finds that as more people were able to manipulate light, the more puzzling and tricky it became. This led to investigations into the strange relationship between light, the eye and the mind, and the development of new technology such as photography and cinema.