Abstract
Papers are discussed in which the quantum dynamics of individual molecules and semiconductor nanocrystals is studied from their fluctuating fluorescence. Presented are the fundamental tenets of the theory of photon emission by a single nanoparticle irradiated by continuous laser light. Fluorescence fluctuations which occur only for single nanoparticles are shown to open up entirely new opportunities for investigating nanoparticle quantum dynamics. It is shown how the theory can be harnessed to analyze the fluorescence fluctuations of an individual polymer molecule and a semiconductor nanocrystal and how the corresponding microscopic models can be constructed proceeding from this analysis.