  I discuss the results for $|V_{ub}|f_+(0)$ and $|V_{ub}|$ obtained from the
spectrum of $B\to\pi e \nu$ and the form factor $f_+(q^2)$ from QCD sum rules
on the light-cone and unquenched lattice calculations; the shape of $f_+(q^2)$
is fixed from experimental data.
