Book excerpt: The internationally renowned physicist Harald Fritzsch deftly explains the meaning and far-flung implications of the general theory of relativity and other mysteries of modern physics by presenting an imaginary conversation among Newton, Einstein, and a fictitious contemporary particle physicist named Adrian Haller. In this entertaining and involving account of relativity, Newton serves as the skeptic and asks the questions a modern reader might ask. Einstein himself does the explaining, while Haller explains the new developments that have occurred since the general theory was proposed.