My research is in general focussed on the nature of galaxies in the early universe. During my graduate studies 1996-2000 I worked on this topic (under the supervision of Palle Møller and Bjarne Thomsen) by studying so called Damped Ly-α Absorbers (DLAs). These objects are high redshift galaxies found via the absorption they cause in the spectra of yet more distant and bright QSOs. The advantage of DLAs for the study of high redshift galaxies is that they are absorption selected from the pool of galaxies present at these early epochs. The consequence of this is that it allows an independent look at the high redshift galaxy population with different selection effects than for high redshift galaxies identified via their emission. Perhaps more importantly a wealth of information about the chemical enrichment of the galaxies can be derived from the study of absorption lines in the spectrum of the QSO due to metals in the absorbers. My thesis can be found here. In my thesis thre were two main results: 1) an exploration of the relation between DLAs and a new population of galaxies called "Lyman-break galaxies" (see below). I found in the thesis that DLAs must belong to a much more numerous population of fainter galaxies than the Lyman-break galaxies found at the time. 2) we found the first (or at least one of the first) example of what has later been known as "Lyman-alpha blobs".