  The damped Lyman-alpha (DLA) and sub-DLA quasar absorption lines provide
powerful probes of the evolution of metals, gas, and stars in galaxies. One
major obstacle in trying to understand the evolution of DLAs and sub-DLAs has
been the small number of metallicity measurements at z < 1.5, an epoch spanning
\~70 % of the cosmic history. In recent surveys with the Hubble Space Telescope
and Multiple Mirror Telescope, we have doubled the DLA Zn sample at z < 1.5.
Combining our results with those at higher redshifts from the literature, we
find that the global mean metallicity of DLAs does not rise to the solar value
at low redshifts. These surprising results appear to contradict the near-solar
mean metallicity observed for nearby (z ~ 0) galaxies and the predictions of
cosmic chemical evolution models based on the global star formation history.
Finally, we discuss direct constraints on the star formation rates (SFRs) in
the absorber galaxies from our deep Fabry-Perot Ly-alpha imaging study and
other emission-line studies in the literature. A large fraction of the observed
heavy-element quasar absorbers at 0 < z < 3.4 appear to have SFRs substantially
below the global mean SFR, consistent with the low metallicities observed in
the spectroscopic studies.
