  This thesis examines the applications and determinations of meson light-cone
distribution amplitudes. The investigation of such processes, in the context of
$B$ physics, provides one with a rich and extensive way of determining the
Standard Model parameters of the CKM matrix, which are essential in describing
CP violation, and searching for tell-tale signs of new physics beyond the
Standard Model. We investigate the twist-2 and twist-3 distribution amplitudes
of light vector mesons and fully examine $\rm SU(3)_F$-breaking effects and
include leading G-parity violating terms. Numerical values of the leading
non-perturbative hadronic parameters are determined from QCD sum rules. The
distribution amplitude results find direct application in the radiative $B$
decays to light vector mesons $B \to V \gamma$. We examine the
phenomenologically most important observables in this decay mode using the
formalism of QCD factorisation. We also include long-distance photon emission
and soft quark loop effects, which formally lie outside the QCD factorisation
formalism. The analysis encompasses all the modes $B_{u,d} \to \rho, \omega,
K^*$ and $B_{s} \to \phi, \bar{K}^*$. We also calculate the $B \to \etapb$
transition form factor using QCD sum rules on the light-cone. We include the
singlet contribution originating from the $\rm U(1)_A$ anomaly and bring the
calculation consistently within the $\eta$-$\etap$ mixing framework.
