While several reviews and books on surface nanophotonics and fluorescence spectroscopy are available, an updated focus on molecular plasmonics, including both theoretical methods and experimental aspects, is still lacking. This handbook is a comprehensive overview on the physics of the plasmon–emitter interaction, ranging from electromagnetism to quantum mechanics, from metal-enhanced fluorescence to surface-enhanced Raman scattering, from optical microscopy to synthesis of metal nanoparticles, filling the gap in the literature of this merging field. It allows experimentalists to have a solid theoretical reference at a different level of accuracy, and theoreticians to find new stimuli for novel computational methods and emerging applications.