We present a systematic treatment of the linear theory of scalar gravitatio
nal perturbations of various matter (including baryons, cold dark matter, p
hotons, massless neutrinos, and massive neutrino) for the flat, open and cl
ose universes, concentrating on the treatment of the massive neutrino compo
nent which has been either ignored or approximated crudely for the nonflat
universe in previous literatures.