Selected topics in the theory of neutrinos, discussed in last years, are presented. We shortly summarize properties of neutrinos in frame of the original Standard Model (SM) and give the experimental information about
their masses and mixing. In the frame of the model with massive neutrinos, the so-called New SM ( SM), two controversial phenomena, the Mössbauer neutrinos problem and the GSI anomaly are explained. Beyond the SM
(BSM) we focus on two issues, on the problem of small neutrino masses and large mixing in comparison to the quark sector and on how neutrino oscillation phenomena should be correctly described in the BSM.