  Heavy-to-light meson form factors at large recoil can be described using the
same techniques as for hard exclusive processes involving only light hadrons.
Two competing mechanisms appear in the large-recoil regime, describing
so-called ``soft-overlap'' and ``hard-scattering'' components of the form
factors. It is shown how existing experimental data from B and D decays
constrain the relative size of these components, and how lattice data can be
used to study properties such as the energy scaling laws obeyed by the
individual components. Symmetry relations between different form factors (F_+,
F_0 and F_T), and between different heavy initial-state mesons (B and D), are
derived in the combined heavy-quark and large-recoil limits, and are shown to
generalize corresponding relations valid at small recoil. Form factor
parameterizations that are consistent with the large-recoil limit are
discussed.
