  The ensemble of light-cone Fock wavefunctions $\{\psi_{n/H}(x_i,\vec k_{\perp
i},\lambda_i)\}$ provides a conceptual basis for representing physical hadrons
and nuclei in terms of their fundamental quark and gluon degrees of freedom. A
number of applications of the light-cone formalism to QCD phenomenology are
briefly reviewed, such as the origin of Regge behavior of polarized structure
functions, the high momentum transfer behavior of exclusive reactions, the
color transparency properties of diffractive vector meson photoproduction, and
the behavior of quark distributions at large $x_{bj}$. The light-cone formalism
illuminates novel features of hadron physics, such as the intrinsic gluon and
heavy quark distributions, the quark - antiquark asymmetry of the intrinsic
heavy quark sea, and the importance of rearrangement mechanisms in heavy
quarkonium decay. I also discuss the potential for measuring the shape of the
valence light-cone Fock wavefunction of hadrons and photons in nuclear
diffractive multi-jet production.
