And discussion of current boundsFuture sensitivities on neutrino masses from cosmology; Conclusions; Neutrin's and the stars; Introduction; Neutrin's from ordinary stars; Some basics of stellar evolution; Neutrino emission processes; Neutrino electromagnetic properties; Globular clusters testing stellar evolution and particle physics; White dwarf cooling; Neutrin's from the Sun; Solar neutrino measurements and flavor oscillations; Helioseismology and the solar opacity problem; Sun as a particle source; Supernova neutrinos; Classification of supernovae; Explosion mechanism