  The primary aim of the thesis is to explore the possibility of spontaneous
symmetry breaking by strong Yukawa dynamics. Technically, the symmetry is
assumed to be broken by formation of symmetry-breaking parts of both the scalar
and the fermion propagators, rather than by the scalar vacuum expectation
values. The idea is first introduced on an example of a toy model with the
underlying symmetry being an Abelian one and later applied to a realistic model
of electroweak interaction. In addition, the thesis also deals with some more
general, model-independent issues, applicable not only to the discussed model
of strong Yukawa dynamics, but to a wider class of models with dynamical mass
generation. First of these issues is the problem of fermion flavor mixing in
the presence of fermion self-energies with a general momentum dependence. It is
in particular shown how to define the Cabibbo-Kobayashi-Maskawa (CKM) matrix in
such models and argued that it can come out in principle non-unitary. Second
issue is the problem of calculating the gauge boson masses when the symmetry is
broken by fermion self-energies. On top of deriving the formula for the gauge
boson mass matrix we also find corrections to the related Pagels-Stokar
formula.
