  Thanks to the accurate determination of the baryon density of the universe by
the recent cosmic microwave background experiments, updated predictions of the
standard model of Big Bang nucleosynthesis now yield the initial abundance of
the primordial light elements with an unprecedented precision. In the case of
$^7$Li, the CMB+SBBN value is significantly higher than the generally reported
abundances for Pop II stars along the so-called Spite plateau. In view of the
crucial importance of this disagreement which has cosmological, galactic and
stellar implications, we decided to tackle the most critical issues of the
problem by revisiting a large sample of literature Li data in halo stars that
we assembled following some strict selection criteria on the quality of the
original analyses. [Abridged]
