The exact sciences have an immense weight and influence in our culture. At the heart of their effectiveness lies the mathematical equation. The difficult form of the great equations - particularly those of modern physics - has often acted as an obstacle to any understanding and they have come to embody the mystery and terror of modern science. This volume brings together well-known scientists, historians and writers about science as each seeks to unpack an equation and explain how it was arrived at, what it can do and what remains to be understood about it. The contributors include Roger Penrose, John Maynard Smith, Arthur Miller, Steven Weinberg and Oliver Morton.