  General properties of the hopping transport of charge carriers in amorphous
organic and inorganic materials are discussed. We consider the case where the
random energy landscape in the materials is strongly spatially correlated. This
is a very typical situation in the organic materials having the Gaussian
density of states (DOS) and may be realized in some materials with the
exponential DOS. We demonstrate that the different type of DOS leads to a very
different functional form of the mobility field dependence even in the case of
the identical correlation function of random energy. We provide important
arguments in favor of the significant contribution of the local orientational
order to the total magnitude of the energetic disorder in organic materials. A
simple but promising model of charge transport in highly anisotropic composites
materials is suggested.
