1. Introduction: The Primordial Flame The universe, in its most fundamental energetic sense, is a fusion engine. From the blinding incandescence of the Sun to the glittering expanse of the Milky Way, the cosmos is illuminated by the violent, beautiful marriage of atomic nuclei. For nearly a century, humanity has looked upon this celestial alchemy with a mixture of awe and envy, recognizing that the power to fuse atoms—to "bottle a star"—holds the promise of an energy source s