  The `strong-coupling' perturbation theory over the inverse interaction
constant $1/g$ near the nontrivial solution of Lagrange equation is formulated.
The ordinary `week-coupling' perturbation theory over $g$ is described also to
compare both perturbation theories. The `strong-coupling' perturbation theory
is developed by unitary mapping of the quantum dynamics into the space with
local coordinates of (action, angle)-type.
