As with most aspects of modern astrophysics, the last few years
have seen a remarkable gathering of new data on chemical abundances
in the high redshift universe. I shall review recent results
on metallicities in galaxies and the intergalactic medium
observed when the universe was 2-3 billion years old. The ultimate
aim is to interpret such chemical clues with a view to establishing
the connection between these early structures in the universe and
the galaxies we see around us today. I shall show that we have made
significant progress towards this goal, although much remains to
be done.