  Using the conditional luminosity function -- the luminosity distribution of
galaxies in a dark matter halo as a function of the halo mass -- we present an
empirical model to describe the redshift evolution of the rest B-band galaxy
luminosity function (LF). The model is compared to measured LFs out to a
redshift of 3.5, including LFs of galaxy types separated to red and blue
galaxies. The increase in the number density of luminous galaxies, at the
bright-end of the LF, can be explained as due to a brightening of the
luminosity of galaxies present in dark matter halo centers, relative to the
luminosity of central galaxies in similar mass halos today. The lack of strong
evolution in the faint-end of the LF, however, argues against a model involving
pure luminosity evolution at all halo mass scales. The increase in luminosity
at the bright-end compensates the rapid decline in the number density of
massive halos as the redshift is increased. The decline in group to
cluster-mass dark matter halos out to a redshift of ~ 2 is not important as the
central galaxy luminosity flattens at halo masses around 10^13 M_sun At
redshifts ~ 2 to 3, however, the density of bright galaxies begins to decrease
due to the rapid decline in the number density of dark matter halos at mass
scales around and below 10^13 M_sun. We compare our predictions to the UV LF of
galaxies at redshifts 3 to 6 and the galaxy clustering bias measurements at
redshifts ~ 3, and use our models to establish the dark matter halo mass scales
of galaxies observed at high redshifts. In general, to explain high-redshift
LFs, galaxies in dark matter halos around 10^12 M_sun must increase in
luminosity by a factor of ~ 4 to 6 between today and redshift of 6.
