Much of our knowledge about the formation and evolution of high-redshift galaxies has come from studying the absorption signatures they impress on the spectra of background QSOs. The damped Lyman α (DLA) systems, in particular, have proved to be valuable probes of the metallicity and dust at redshifts z ~2-3 in what are the likely progenitors of galaxies like our own. At z ~ 2 we find that the typical metallicity of the universe was 1/15 solar. In addition, we find clear evidence for the existence of trace amounts of interstellar dust in DLA galaxies and show that this is consistent with recent high resolution spectra of DLAs with the Keck telescope, despite claims to the contrary.

• RICHARD W. HUNSTEAD(School of Physics, University of Sydney)
• MAX PETTINI(Royal Greenwich Observatory)
• DAVID KING(Royal Greenwich Observatory)
• LINDA J. SMITH(University College London)