This is the title of a talk I gave on March 9, 2023, at a special Symposium of the Spring Meeting of the Section on Atomic, Molecular, and Optical Physics of the German Physical Society. The purpose of the Symposium at the University of Hannover was to honor and recognize over 50 years of work by a colleague of mine, Professor Eberhard Tiemann. Eberhard’s seminal work in molecular spectroscopy has been essential to a body of international research over the last 3 decades involving many fruitful research directions with ultracold matter. The field of molecular spectroscopy deals with the “spectrum” of discrete wavelengths (or “spectral lines”) absorbed or emitted by a specific molecule.