  In the last decade, the LEP and SLD experiments played a central role in the
study of B hadrons (hadrons containing a b quark).
  New B hadrons have been observed ($B^0_s$, \Lambda_b$, $\Xi_b$ and $B^{**}$)
and their production and decay properties have been measured. In this paper we
will focus on measurements of the CKM matrix elements: $|V_{cb}|$, $|V_{ub}|$,
$|V_{td}|$ and $|V_{ts}|$. We will show how all these measurements, together
with theoretical developments, have significantly improved our knowledge on the
flavour sector of the Standard Model.
