  I briefly review the description of inclusive heavy hadron decays based on
the inverse heavy quark mass expansion. In particular, I consider the
transition $B \to X_u \ell \nu$ and the problem of extracting $V_{ub}$, mainly
as far as the separation from the background represented by $b \to c$ modes is
concerned. I also discuss how to obtain complementary information from the
decay mode $B \to X_s \gamma$.
