The monograph describes the scientific direction "Diagnostics of macroscopic volumes of solid disordered media with nanometer spatial resolution by spectra and fluorescent images of many single probe molecules," developed as part of the author's doctoral dissertation. The possibilities of spectroscopy and fluorescence microscopy of single molecules for studying low-temperature dynamics and local structure of disordered solid-state media are considered; experimental methods and theoretical approaches to describe experimental data. The results of experimental and theoretical studies of the dynamics of a wide range of oligo- and polymers, organic glasses and polycrystals at low temperatures (1.5-40 K) are presented. It is shown how this approach can be used in the applied field for nanodiagnostics of materials with a complex microstructure. The monograph can be used as a teaching aid and is designed for senior students, graduate students and novice researchers working in the field of selective laser spectroscopy of complex organic compounds and nanostructures.