This paper analyzes available data on the synthesis and properties of polymer nanocomposites prepared by various techniques (sol-gel processing and microemulsion and frontal polymerizations) and containing polymethyl methacrylate, polydimethylsiloxane, natural rubber, and other polymers as binders, and various amounts of nano- and microadditives: SiO2, TiO2, FeO, clay, and Y1Ba2Cu3O7 − x. We consider the physicomechanical, dynamic mechanical, superconducting, thermophysical, thermochemical, and other properties of the polymer nanocomposites.