A quantitative theory of anionic copolymerization of an arbitrary number of monomers has been developed to calculate the rate of this process as well as the parameters characterizing the composition and chemical structure of the gradient macromolecules formed. Equations have been derived for the angular dependence of the amplitude of scattering of the melt of these copolymers as well as its spinodal. The theory elaborated for batch "living" anionic copolymerization has been extended to semibatch regimes where the reaction mixture is continuously fed by a solution of monomers. Equations have been derived providing the possibility to establish the dependence of the intramolecular inhomogeneity of the products of semibatch copolymerization on the monomer feed rate and composition. With the theoretical approach developed, it is possible to efficiently control the chemical structure of the copolymers at each stage of their synthesis which is of utmost importance for obtaining polymeric materials with desired properties.