Despite its discovery half a century ago, the photoluminescence (PL) of metals has only recently gained prominence due to advances in the production of plasmonic nanostructures. Renewed interest first arose from the desire to remove the spurious background in surfaceenhanced Raman spectroscopy (SERS). Newer studies attempt to utilize metal PL in different applications, e.g. for imaging and sensing purposes or employ it as experimental probe, e.g. to access the charge density in plasmonic nanoparticles, to study charge transfer, or to measure temperatures on the nanoscale. Notwithstanding this growing number of applications, a comprehensive understanding of metal PL has not yet been achieved. A major challenge is the potential existence of numerous emission mechanisms, particularly in materials, which exhibit pronounced interband transitions close to the plasmon resonance wavelength, such as the ubiquitous gold.