  The short review of theoretical aspects of ultra high energy (UHE) neutrinos
and superGZK neutrinos. The sources and diffuse fluxes of UHE neutrinos are
discussed. Much attention is given to comparison of the cascade and cosmic ray
upper bounds for diffuse neutrino fluxes. Cosmogenic neutrinos and neutrinos
from the mirror mater are considered as superGZK neutrinos.
