  The concepts of effective and dynamical neutrino mixing matrices are
introduced in order to describe the behavior of neutrinos in matter. The former
relates weak eigenstates to mass eigenstates, whereas the latter relates weak
eigenstates to energy eigenstates in matter. It is shown that the dynamical
mixing angles enable us to express the neutrino survival probability in the Sun
without any resort to the Landau-Zener transition probability for the
non-adiabatic process. Also discussed are effective CP violating phases that
appear in the effective and dynamical mixing matrices in matter. Both two and
three generation cases are discussed using the solar neutrinos as an example.
