  In this work we describe the Correlative Method of Unsymmetrized
Self-Consistent Field (CUSF). This method is based on a set of nonlinear
integrodifferential equations for the one-particle configurational distribution
functions and for the self-consistent potentials of the atoms. Here we present
the fundamental concepts of the CUSF, the hypotheses of the method, the basic
equations, the self-consistent potential, the thermodynamics of the anharmonic
crystalline solids, and the quantum corrections in the quasi-classical
approximation.
  Keywords: lattice theory and statistics; anharmonic crystals; thermodynamics.
