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I began my graduate career working with Jane C. Charlton and Christopher W. Churchill in the fall of 1996, after I graduated from the University of Arizona with a B.S. in Physics and Astronomy. Chris was a beginning his first postdoc, and had done his thesis work on intermediate redshift Mg II-selected quasar absorption lines systems, for which he obtained a sample of high resolution spectra from the W.M. Keck I observatory (with the HIRES instrument). My first project was to search these spectra for systems selected by the C IV 1548, 1550 doublet, which in the optical spectra lay at higher redshift. In the course of this study, which has never been published, I found the subject of my second year project, and an avenue for my doctoral work.

The second year project came about when examining a particular C IV system at z=1.937294 toward the quasar PG 1222+228 (z=2.038). In the Keck I/HIRES spectra, I also detected transitions from Si II, Si IV, Al II, and Al III. The velocity distribution of gas revealed something very striking - one absorption component showed Si II and no Al II or Al III, while another only 15 km/s away, showed just the opposite. The only way this would be possible is through an abundance variation in a system. It was an interesting result and marked the time our group attempted to understand the physical conditions of an absorption system. In a broader context, we had taken a step toward examining individual leaves in a tree of the Lyman alpha forest.

I continued studying these C IV systems and found a few that I simply could not understand. In the effort to fit C IV profiles to obtain column densities, I found a subset where the optical depth ratio was not 2:1 as expected for unsaturated doublets. The reason for this, and the subject of Chapter 2, is partial coverage of the background quasar. (One of these systems was again toward PG 1222+228, and so, this quasar will always find special place with me.) This began my descent to the ``darker side'' of quasar absorption line research - absorption intrinsic to the quasar - from which I do not intent to re-ascend.