It is the most famous equation in the world, and yet most of us do not know its significance. Leading theoretical physicist Christophe Galfard, who was trained by Stephen Hawking, explains it all in a way that is accessible and pertinent to the world in which we live in. The beginning of the 20th century heralded a scientific revolution: what a few brilliant minds uncovered about our reality in the first twenty years has shaped the history of our...