Near-pristine gas at high redshifts: a window on early nucleosynthesis
  It has now become recognised that damped Lyman alpha systems play an
important role in helping us unravel the origin of chemical elements. In this
presentation, we describe the main results of a recently completed survey of
the most metal-poor DLAs, aimed at complementing and extending studies of the
oldest stars in the Galaxy. The survey has clarified a number of lingering
issues concerning the abundances of C, N, O in the low metallicity regime, has
revealed the existence of DLA analogues to Carbon-enhanced metal-poor stars,
and is providing some of the most precise measures of the primordial abundance
of Deuterium.
