A number of studies is reviewed that has been conducted in recent years on three current problems of the theory of disordered semiconductors: a) The nature of the electron states in systems of different dimensionalities (including the problem of the so-called ``power-law'' (``weak'') localization), b) Some multielectron effects in disordered semiconductors (including the problem of the Coulomb gap), c) Absorption of light with quantum energies smaller than the optical width of the forbidden band (including an analysis of the role of macroscopic inhomogeneity of thin films).