  After few minutes the Universe evolved through conditions of temperature and
density which permitted the first synthesis of astrophysically interesting
abundances of D, 3He, 4He and 7Li. The relic abundances are sensitive probes of
the nucleon density and so are the CMB acoustic oscillations, somewhat 400000
years later, which allow a stringent cross check. The CMB high precision
estimate of the baryon density by WMAP is currently used as input parameter for
standard big bang nucleosynthesis (SBBN) to interpret primordial bundances
rather then being directly derived from the observations of light elements as
was common use before. New atomic physics and identification of systematics
lead to an upwards revision of the 4He primordial abundance at Yp=0.2477 +/-
0.0029 (Peimbert et al 2007) removing a major source of tension between SBBN
and WMAP. The D/H as measured in QSO high redshift absorbing clouds shows an
excess of scatter but the mean value is found in spectacular agreement with the
WMAP prediction. The Li/H recently redetermined in halo dwarfs is more than a
factor 4 lower than expected. We argue that the difference reduces to a factor
2 when the IRFM Teff scale is adopted. Diffusion has been suggested to have
depleted Li in halo dwarfs by the required amount to remove the gap, however
this would imply an implausible high abundance of the more fragile 6Li detected
in some halo dwarfs, thus leaving the puzzle open.
