The theoretical department was created in 1966 as an initiative of academician A.V.Shubnikov. The real crystal theory became its main direction of study. The founder and the first director of the department was the famous soviet scientist professor V.L.Indenbom. With his direct participation several important works on dislocations theory have been made: the common methods for elastic dislocation fields calculations in anisotropic phases were developed as well as the approaches to the search for the equilibrium dislocation configurations; the dynamical dislocation braking due to the dissipation processes in phonon and electron subsystems of a crystal was studied as well as dislocation kinetics in the potential relief of crystal lattice with local barriers due to point defects; the conformity to natural laws of the plastic deformations in high and low temperatures was explained.

The geometrical and diffraction optics of Bloch waves in imperfect crystals, x-ray dislocation image and single ray electron microscopic contrast theories were developed.

Besides, several works about the phase transitions theory and symmetry have been made: the connection between black-white and color symmetry and one-dimensional representations of the crystallography groups was shown; the theory of phase transformations between crystal classes was suggested; the existence of modulated ferroelectrics was forecasted.

Then, the liquid crystal theory has been developed: the thermodynamic states of mezophases were classified; the phenomenological and microscopic theories of ferroelectric liquid crystals were suggested as well as the common approach to the modulated structures in anisotropic substance.