The metal/carbon nanocomposites (NCs) properties are considered in this chapter. The theoretical and experimental methods give possibility to prognosticate and to lead the experimental estimation of influence of NCs on changes in the polymeric media electron (submolecular) structures are discussed. The NC electromagnetic field action on the medium molecules leads to the medium molecule self-organization and to the formation of nanostructured fragments (fractals) in the material composition. These changes can be accompanied by the processes of active particles appearance. The changes of media electron structure are possible under the influence of minute quantities of NCs, which is confirmed by the X-ray photoelectron spectroscopic investigations. The mechanism of polymeric materials modification processes by supersmall (minute) quantities of metal/carbon 144NCs is proposed. The estimation methods of self-organization in polymeric compositions and materials, modified by minute quantities of metal/carbon NC, are also proposed. The orientation processes, in which mesoscopic particles (NCs) participate, lead to the changes of submolecular structures and properties of materials. Usually in the process of polymeric matrix, self-organization stimulates the increase of material heat capacity, the material density, its thermal stability, and also the adhesive strength. The improvement of other properties of materials, modified by the supersmall quantities of metal/carbon NCs, is also possible.