Unlike the myriad points of light we gaze at in the night sky, our nearest star allows us to study the wonders of stellar workings at blindingly close range - from a mere 93 million miles away. And what do we see? In this book, two of the world's leading solar scientists unfold all that history and science - from the first cursory observations to the measurements obtained by the latest state-of-the-instruments on the ground and in space - have revealed about the Sun. Following the path of science from the very centre of this 380,000,000,000,000,000,000-megawatt furnace to its explosive surface. This text invites readers into an open-ended narrative of discovery about what we know about the Sun and how we have learned it. How did the Sun evolve, and what will it become? What is the origin of its light and heat? How does solar activity affect the atmospheric conditions that make life on earth possible? These are the questions at the heart of solar physics, and at the centre of this book. Having made optical solar observations with many solar telescopes and in the rockets and satellites, the authors bring their extensive personal experience to this story of how astronomers study the Sun, and what they have discovered about phenomena from eclipses to neutrinos, space weather, and global warming.