Could nanotechnology become humanity's greatest achievement or our final mistake? Leading nanotechnology journalist Douglas Mulhall explores the revolutionary potential and terrifying dangers of molecular-scale engineering. Mulhall examines how nanotechnology enables the creation of devices smaller, more powerful, and more efficient than ever imagined, with applications spanning medicine, computing, and materials science. The discussion delves into the darker possibilities, including the nightmare scenario of "gray goo" where self-replicating nanobots consume all matter on Earth. Art and Mulhall explore ethical concerns about nanotechnology's rapid development outpacing our ability to understand its implications, much like nuclear technology in previous decades. They discuss potential weaponization of nanotechnology, from nanoneedles that could manipulate individual atoms to molecular machines capable of rewriting biological systems. The conversation addresses how nanotechnology investment is accelerating despite inadequate safety protocols and regulatory frameworks. This technological examination reveals how we stand at a crossroads where our greatest scientific breakthrough could either solve humanity's problems or create unprecedented existential threats.