Conventional melt-state processing of polymer-nanofiller hybrids is accompanied by a series of thermodynamically and kinetically based stumbling blocks that have proven very difficult to overcome in the production of well-dispersed or well-exfoliated nanocomposites, regardless of the type of nanofiller or nanoparticle (e.g., clay, carbon nanotubes, etc.). Here we demonstrate that a novel, industrially applicable process method called solid-state shear pulverization (SSSP) can be used to overcome or make inoperative some fo the stumbling block associated with conventional melt processing of polymer nanocomposites, resulting in the achievement of excellent nanofiller dispersion or exfoliation. Examples to be described include polymer-clay nanocomposites involving the use of nonpolar polymer, polymers with very high melt transition temperatures, and polymers with low thermal stability. We shall also provide examples indicating that excellent dispersion and enhanced properties can be achieved by SSSP using carbon-based nanofillers. In particular, we shall provide examples in which the following property changes result from nanofiller addition: reduction in O2 permeability coefficient by 60+%, increase of tensile modulus by 105%, increase in degradation temperature by 30+ K, increase in electrical conductivity by a factor of 1000, and enormous changes in crystallization rates of semi-crystalline polymers. Control and tuning of these property enhancement via level and dispersion of the nanofiller will be discussed