Bogolyubov generating functional method in statistical mechanics and the analog of the transformation to collective variables

]3ogolyubov's functional equations for the distribution functions in statistical mechanics for equilibrium and nonequilibrium many-particle systems are studied. An analog of the transformation to "collective" variables on the basis of an exact solution of ]3ogolyubov's functional equation in the equilibrium case is proposed. ]3ogolyubov's method is used to obtain a functional equation of Kirkwood-Salsburg-Symanzik type. A path integral method is developed for constructing the generating functionals of the distribution functions.