  We used ultraviolet spectra from HST/STIS (R=30,000), together with optical
spectra from Keck/HIRES (R=45,000), to study the three MgII-selected absorption
systems at z=0.9254, 0.9276, and 0.9342 toward the quasar PG 1206+459. A
multi-phase gaseous structure, with low-ionization components produced in small
condensations and high-ionization ones in diffuse clouds, is indicated in all
three systems. Each system is likely to represent a different galaxy with
absorption due to some combination of interstellar medium, coronal gas, halo
gas, and high-velocity clouds. Even with the improved sensitivity of HST/COS,
we will only be able to obtain high-resolution ultraviolet spectra of the
brightest quasars in the sky. A larger telescope with ultraviolet coverage will
enable quasar absorption line studies of hundreds of galaxies, including a wide
range of galaxy types and environments at low and intermediate redshifts.
