  The review of the modern results in the theoretical and experimental study of
the localized interacting electrons is given. After theoretical prediction of
the Coulomb gap and the new temperature law in the variable range hopping
conduction many efforts have been made to discover it experimentally. The most
important of them are attempts to demonstrate experimentally that the long
range Coulomb interaction is not screened in this system and that it is the
origin of the gap. The next stage begins when the recent experiments have
discovered glassy properties of the interacting system with localized
electrons. This review is concentrated on the origin of the glassy properties
of this system and it connects the glassy properties with another interesting
phenomenon - insulator-metal transition.
