What if we could travel through the microscopic world and enter the amazing environment of a single, solitary, minuscule human cell—just one of the trillions in your body? What an amazing world of wonder we would encounter! There, within this infinitesimally small and elegantly ordered domain, we would see complicated molecular machinery busily carrying out the functions that make our lives on earth possible! Traveling to the heart of the cell—its nucleus—we would find the “brains” of this invisible, unfathomably small world: an incredibly thin, unbelievably long strand of atoms that form a molecule, the existence of which is truly a miracle.