  We study the exclusive leptonic and semileptonic $B$ decays $B \to \ell^-
\bar\nu$ and $B \to D^{(\ast)} \ell^-\bar\nu$ in the framework of the covariant
quark model with built-in infrared confinement. We compute the relevant form
factors in the full kinematical momentum transfer region. The calculated form
factors are used to evaluate branching fractions and polarization observables
of the above transitions. We compare our results with experimental data and
results from other theoretical studies.
