The song of the universe. A friendly contest between the four interactions -- Gravity is absurdly weak -- Detection of electromagnetic waves -- From water waves to gravity waves. Spooky action at a distance -- Greatness and audacity: Enter the field -- Einstein, the exterminator of relativity -- Einstein's idea: Spacetime becomes curved -- How to detect something as ethereal as ripples in spacetime. Getting the best possible deal -- Symmetry: physics must not depend on the physicist -- Yes, I want the best deal, but what is the deal? -- The action for Einstein gravity -- It must be. From frozen star to black hole -- The quantum world and Hawking radiation -- Gravitons and the nature of gravity -- Mysterious messages from the dark side -- A new window to the cosmos. What does curved spacetime mean?